Sarika, you make a very good point about the relative merits of city life and country life being a recurring theme in JA.
Austen herself had experience of both. It is clear from letters she wrote during visits to London that she appreciated the cultural life, especially the theatre, and she certainly made the most of the opportunities for shopping, even with her limited income.
But country life was what she preferred, and that shows in her novels.

You post gave me much food for thought, and I would like to offer a different perspective on some of what you say. My comments to London in particular.

Sarika wrote:
"cities then were by far less polluted/populated and still retained a "brit population"(unlike so many immigrants now)"

Population: London had been growing steadily through the 18th century. Some of this growth may can be attributed to slowly declining infant mortality, but mostly it was fuelled by people (mainly young adults) coming from other parts of the country in search of work, as well as excitement and pleasure.
The population of London recorded in the 1801 census was around one million (the exact figure depends on which areas on the periphery of London are included), and by 1815 this had risen to about 1.4 million. London was the largest city in the world, and the population continued to grow rapidly through the 19th century.
Of course these figures are much smaller than today's population of about seven million. But I am sure that from the perspective of someone in Regency England the size of London then would have seemed overwhelming - there simply wasn't anywhere else like it.

Foreigners: London was a major international sea port, which brought many foreigners connected with trade and shipping. Many of these people were transient, but there were also significant numbers of permanent residents who were of foreign origin. London has been a 'melting-pot' city for centuries. The numbers may not have been as great as today, but again I think we need to 'see' Regency London through Regency eyes. Travel was difficult and expensive, many people rarely moved far from where they were born, and a person from fifty miles away with a slightly different regional accent might well be perceived as 'foreign'. I think that people coming to the capital from other parts of the country would certainly notice that London's population included people of many different races and cultures.

The link at the foot of this post is to a page about London's population on the 'Old Bailey' website. This website is well worth exploring because it contains an astonishing amount of detail about the social history of London, including a section on various immigrant communities.

Pollution: If we could travel back in time to Regency London I very much doubt that we would think it was less polluted than today.

Underfoot: We rely on the internal combustion engine; they relied on horses, which produce their own form of under-foot pollution - in quantity! Add to that the effects of cattle, sheep and pigs livestock being driven through the streets to markets where they were not only sold but slaughtered.....
Here's a page about the great cattle market at Smithfield, (warning - not for the squeamish!). Leadenhall Market, where sheep and pigs were slaughtered, is just at the top of Gracechurch Street. Frankly I'm not surprised if Miss Bingley preferred to remain in the fashionable West End and avoid such inconveniences as much as possible. Her mistake was to despise the inhabitants of Gracechurch Street out of pure smobbery.

Sanitation: Sewerage systems were primitive, the population was rising rapidly, and the infrastructure wasn't keeping pace. The problem got a lot worse before it got better. Try googling ''London', The Great Stink' and 'Cholera' for the details.

Air pollution: London relied on coal for heating, cooking and fuel for many industries. Coal fires produce a lot of soot, which got everywhere.
The following pronouncement on male attire is attributed to the dandy Beau Brummell by his first biographer Captain William Jesse:
"No perfumes, but very fine linen, plenty of it, and country washing.",
The point being that you had to had to send your laundry out to country villages away from all the smoke if you wanted it to come back clean.

Those fashionable white Regency dresses must have been a nightmare to keep clean in London - with all that smoke around they would looked grubby within a few hours. I suspect that for everyday wear they would only have been practical for women who had enough money to change their clothes several times a day and pay for lots of laundry.

A more serious effect of all those coal fires was smog. We tend to associate this with our images of Victorian London, but the problem had been a cause for concern for centuries.

In 1817 Sir Richard Phillips described the smoke of London spreading twenty or thirty miles from the metropolis and killing or blighting vegetation. He goes on to say:

"Other phenomena are produced by it's union with fogs, rendering them nearly opaque and shutting out the light of the sun; it blackens the mud of the streets by it's deposits of tar, while the unctuous mixture renders the foot-pavement slippery; and it produces a solemn gloom whenever a sudden change of wind returns over the town the volume that was previously on it's passage into the country."
( "A Morning's Walk from London to Kew" (page 11) Sir Richard Phillips, 1817. Googlebooks text is online.)

The smog problem was not dealt with effectively until the Clean Air Act of 1956. When I was young (back in the Dark Ages) London was widely referred to as "The Smoke".

With problems such as these (and for other reasons) most people from the gentry and aristocracy preferred to have their primary home in the country rather than in London.

Nevertheless, London had it's devotees, and not only people with dubious morals like the Crawfords. Samuel Johnson (of dictionary fame) loved the place for the intellectual stimulus it offered, and said to James Boswell in 1777:
"Why, Sir, you find no man, at all intellectual, who is willing to leave London. No, Sir, when a man is tired of London, he is tired of life; for there is in London all that life can afford."

My favourite quote on the subject is from the clergyman and wit Sydney Smith (1771-1845), who wrote in about 1797: "I have no relish for the country; it is a kind of healthy grave."

Then, as now, many people preferred the country but others were happier with life in town. Though the details may have changed, it is surprising how often the choices and dilemmas confronted by JA's characters have parallels in our own times.