This just isn't true on any measure (apart from affordability and true high speed penetration in some countries).
Affordability is really driven by how much the operators are subsidized by the govt. It's hard to calculate this on a like for like basis as some subsidy goes to the track operator and some to the train operator, and in eg Germany you have a hugely complex set of subsidies and fare zones in operation from various levels of government.
I don't expect the other European systems to be any cheaper - it's just hidden in the tax system instead.
Where the UK shines imo is two things. 1 is the frequency of many services. It's rare to have less than 2 trains per hour on an intercity route, and often far more.
This compares to France (outside TGV) which is atrocious. Non regular timetable with often 2-3 hour gaps on trains.
Spain (even on the high speed lines) is even worse. Some _high speed lines_ can't even manage an hourly service. This has got far better recently on high speed lines with private competition, but outside of that the timetabling is terrible.
The other is some of the ticketing options. Firstly, there is a no questions asked delay repay feature which means you get a substantial portion of the ticket refunded if there is any delay for any reason, starting at a 15minute delay. Obviously no delays are better than a refunded one, but I've had some atrocious delays in mainland europe and no option to apply for a refund.
The other is no composlary reservations (though I'm not sure how long this will last). If you have a valid ticket, you can get on. In many EU countries if a train is out of seats you don't even have the option to buy a ticket and stand. Combine this with poor timetables on many routes and it can cause huge problems if you are travelling at short notice.
Netherlands and Switzerland good for sure - better than the UK I would say. But Germany/France/Italy/Spain have a lot of issues.