I fear that you may well have only seen London stations, there's quite a lot of the South East which is fairly similar to what you are describing.
When I lived with my parents or was well over a mile to my nearest station whilst to the station we used the most was 3 miles away.
Even when I moved out it was between a 10 minute walk and 3 miles depending on where we were living at the time to the nearest station.
Even though there's problems with car parking some of this could be resolved by providing better cycle parking and better cycle facilities.
Yes, we could improve options for hardly any money whatsoever with massive investment in bike parking, and no that is not a contradiction in terms. Compared to car parking massive investment in bike parking is cheap as chips. Take my regular haunts. Herne Hill, Brixton, Paddington, Victoria, Leeds, Euston, Liverpool Lime Street, Headingley Southport, Wigan. Dreadful provision at all of them. Everything that is there full all the time and before the armchair moaners kick in, no not all with abandoned bikes. Before we encourage people to get in their car for 5 mins we could encourage and prioritise everybody who would happily get on their bike for 5 - 10 mins. That gives you a wider circle around a station than the 'walkers' circle. From my front door to Herne Hill station - 20 mins walking, 5 mins on bike.
Headingley, classic example. Station in slightly odd place but massively congested roads into Leeds all around. Now to have a 15 minute service - that is turn up and go. Student and commuter heartlands, thousands of potential users within 10 mins ride. Absolutely screw all bike provision. No way I would leave my bike there.
Merseyrail is the only network I know to have got it anywhere near right.
Add secure parking for electric bikes, you widen the circle even more. Easily to those 30-40 mins walk out and you probably also unlock stations in hilly areas.
We really are weird in this country. Fine, some people insist on using their car but plenty are being held back from using bikes for want of some secure bike parking with CCTV. I have had two bikes nicked in my time. One from on street outside Kings Cross, one on street from outside Denmark Hill. Great nicking fodder for the scumbags because they know you might be gone for a while.
After you have prioritised bike parking, prioritise bus routes to stations. Look at Brixton tube in the morning. Because they forgot to extend the Victoria line a decent distance because it is south of the river (the best option) everybody arrives in on bikes or buses. Thousands upon thousands of people doing the bus/tube transfer every hour making it one of the busiest tube stations in London.
Prioritise spending on unlocking thr maximum extra low carbon journeys for the minimum number of pounds. Those that insist on using cars might have to wait until the autonomous car sharing utopia of the future becomes a reality. The price of land acquisition and construction is eye watering in many cases.