On the contrary, it has never been more popular. Numbers are not that easy to come by but there were 750k tickets sold in 2024. In 1991 400k tickets were sold, the highest since the inception of interrail, but they rest of the 90s saw a slump in ticket sales with most years under 200k.

So Interrail is either close to double as, or even several times more, popular than when you did your trip.