How many times have you used the trains?
Conversely to your experience I've used cross country trains dozens of times and have only had to stand once (I think) and that was on the local leg of the journey. The trains have always been on time as well. Local trains on the other hand can be nasty, 10-15 minutes late and having to stand quite a lot. But that's what you get when travelling on a mainline from london at rush hour...
I used to use trains quite a lot to get from London to Preston, but then I got a car and used that because it is better and cheaper. Almost every time I did the journey on a Friday/Sunday evening some poor sods had to stand up for a long time (the first time it was me!). I never realised that you could buy a first class ticket and have to stand up.
EDIT: And as for other countries, rail travel isn't much better either. Spain I've had to sit on the floor on a 5 hour journey because there were no seats for example... And TBH outside of europe I wouldn't travel standard class at all...
Just because other countries have crap rail services, it doesn't mean we have to have one as well.