You are perhaps of a different generation. In the 1980s, it was possible for young people in Europe to get a all-in-one ticket where you could travel as much as you could for four weeks in the summer. The tickets costed about 250 €. It was a bit a thing that defined my generation. People who traveled on budget did meticulous time-tables to spend as few nights as possible in paid hostels, traveling to Paris then to Vienna to Athene to Rome then to some small place in Portugal and so on. Returning hungry, exhaustauted and longing for a good shower but with bright eyes and full of experiences, meeting unknown people, made many new friends, and seeing a nice bit of the continent.

It is perhaps one of the reasons why my generation defines itself as Europeans. And it is utterly painful to me that my young niece and her generation, at least at the moment, can't do it.

You can still do Interrail! Me and my wife did it a couple of summers ago, a great experience. We weren't on a budget so we got to stay at a few nice hotels. Half a grand tour -- Copenhagen, Berlin, Prague, Budapest, Vienna, Žagreb, Trieste, Florence, Milan, Venice, Zürich... I can warmly recommend it. We would have loved more night trains so I am eagerly awaiting the new Stockholm-Berlin sleeper.

I did internships twice in Europe in 2005 and 2007 and used railpasses to travel on the weekends to other countries. They were a lot more than 250 € but it was worth the experience and learned a lot in the process.

China is another story -- there are no rail passes and you don't need one. The night trains are not that expensive and extremely clean and comfortable.

It is still possible: https://www.interrail.eu/ . I took a 3-months sabbatical last year and did it before arriving in Spain and did the Camino de Santiago :). One of the best experiences ever!

My wife and a friend did this about 6 years ago but it was tragic, in a way, that they almost always ended up taking cheap flights or the odd intercity bus instead of the train because it was just cheaper.

Covid of course has caused all sorts of issues but that’s an odd thing to find utterly painful compared with everything else. There’s always next year.

...Brexit...

British people will be able to do "EURail", as non-European free currently do.

(Or maybe they will stay in the existing system. Turkey seems to be in it.)

https://www.eurail.com/en/eurail-passes

Limited to 90 days because the over 50s decided to remove rights from their children that they themselves enjoyed.

Firstly, that's how democracy works; those people are as entitled to a vote as anyone else. Secondly, 48 percent of 35-44-year-olds and 38 percent of 25-34-year-olds voted for Brexit.

While it’s not a requirement of brexit it’s likely.

Brexit doesn’t stop 27 forward looking countries from enjoying Interrail though.