Make locals aware a station exists? How do we survive in South London then? Putney had a usage of 11 million - double East Putney tube. Penge West (6tph Overground/Southern) has a lower usage than Penge East (4tph Southeastern). The SWT suburban stations apart from North Sheen, Berrylands, Strawberry Hill as well as the Shepperton, Chessington & Hampton Court branches have high-very high usage. As did the Shenfield Metro before TfL operation. If the frequency and population is there then the passengers will be.
You don't get many Tube services in South London! And Putney, despite having both London Underground and National Rail, has two things helping the National Rail station: Location, and speed of services.
Putney is located in the main town centre (even if towards one end), with a large number of bus routes passing it, whereas East Putney is a 5 minute walk down the A205 South Circular Road with less bus routes passing. And in the case of Putney Bridge, it also happens to be the wrong side of the river and in a side road.
From Putney to the Victoria Line at Vauxhall is just a 12 minute journey even on the stopping services, and an easy interchange. Going from East Putney to Victoria takes 21 minutes, almost double, and you've got the issues within the station at Victoria as well. Even if going to Victoria itself a change at Clapham Junction is less than 5 minutes slower, but potentially with an easier exit from the station. For interchange to the Jubilee Line, there is a negligible time difference between the District Line at Westminster and SWT at Waterloo.
In comparison, Hounslow also has both National Rail and Tube services. But here the Tube stations Hounslow Central (4 million usage) and Hounslow East (4.6 million usage) are located a 5 minute walk from each end of the shopping areas, with several bus routes nearby, and the line is high up on an embankment which can be seen from the western end of the main High Street itself. In comparison, the National Rail at Hounslow (1.2 million usage) is a 10 minute walk from the nearest point of the town centre, runs at ground level so is well tucked away, is in a higher Travelcard zone, and only one bus route passes it. It is definitely less well known than the Tube route, which helps it be so quiet off peak and means even a 4 coach train is more than enough.
There is also a negligible journey time difference between both routes to either the Victoria Line or Jubilee Line, and to Victoria the SWT with a change at Clapham Junction is a good 10 minutes slower, so people might as well use the 12tph Piccadilly Line instead of the 4tph SWT.
Agreed.
Currently, GN is my road less travelled to avoid the crowds, but I also see the general struggles to get home from the City and West End from other people.
Not as packed as the Piccadilly Line trains. I sometimes have to resort to using GN at times when the Piccadilly Line is so rammed with people that I have to let 3 trains pass by before I can get on.
And knowledge of alternative routes help immensely during times of disruption. My mother didn't even know the existence of New Southgate until I told her when the Piccadilly Line was part suspended, and she had to be at work in the West End in an hour. She got there with plenty of time to spare, which wouldn't have been possible if I wasn't a rail enthusiast.
However, I can see your point. Without more capacity and more frequent trains, the disadvantages could outweigh the advantages. I still don't see how TfL could vastly improve the GN line when the DfT sets service frequencies and Moorgate has a certain capacity. And bus routes to GN stations are less good than their tube stations.
So while ideally, I would love the load to be spread between the Piccadilly and GN lines, as a GN commuter, there are indeed lots of hurdles to overcome for that to happen.
That sounds similar to my dad. He has lived in the Southall/Hounslow area since 1990, but didn't use SWT from Hounslow until 2013. We were going to watch cricket at The Oval (nearest station Vauxhall or Oval), and he was studying hard at the Tube map trying to think of a quiet place in Zone 1 to change between Tube lines during the morning peak. I told him it can be done by direct train, but he didn't believe me at all until I showed him the timetable! I had only used that route for the first time in 2012, but it was a friend that first introduced me to the national rail lines in South London; until then I wasn't particularly aware of them. I remember sending my uncle to East Croydon using Piccadilly and District lines via Hammersmith and Victoria

, the route suggested by TfL journey planners, when going just a mile further down the road in Hounslow would mean avoiding not only busy trains and interchanges, but also Zone 1, even if it was 10 minutes slower by journey time. I wonder how many other people clog up busy Zone 1 Tube interchanges unnecessarily?
After starting uni on the other side of London the SWT route to Waterloo then Jubilee Line has become my route of choice, even if slower. Avoids the crowds on the Piccadilly Line, keeps me above ground in larger more comfortable trains (73ts ride quality is so poor), and guarantees me a seat for the main leg. When speed is important the GW route from Southall to Paddington gets wheeled out, but off peak having 2 trains in 7 minutes then a 23 minute gap puts me off using it more.
The Tube map published by TfL is widely available and well known, but there is a "London's Rail & Tube services" map, an ATOC publication which shows everything, but isn't particularly easy to find displayed in TfL stations, and even harder to find in leaflet format, only being found at select National Rail stations. Personally I see no good reason why TfL cannot adopt the full map as the standard rather than their map that only shows the services that they operate.