Of course, it takes close to an hour to get from central Paris to CDG via the RER trains, then you need to be beyond security at least 45 minutes before the flight goes. At the Basel end, the airport is a distance outside Basel (it is shared with Mulhouse, France and Freiburg, Germany).
So the trip takes about the same amount of time whether by air or rail.
Sure, I’ve been to Basel a number of times. Paris, too. But I’ve only ever driven to Switzerland (from both Italy and Germany).
I did take the train from Kaiserslautern to Paris many times and thoroughly enjoyed it.
Europe does have nice trains. The farther you go, however, the more air travel is required.
I spent time in Greece (Crete) and the UK (pre-Chunnel), too, but flying to those places was necessary.