Your example assumes the same level of quality and guarantee of timely arrival.
Maybe it's just me but I've had such bad luck with trains in Germany that if I need to be somewhere I will fly or take a train one hour earlier. Or two. It was a running joke at my former company that every single time I visited our other office my reserved spot in an ICE was cancelled or the whole train was changed to an IC (yay, working with a laptop on your lap).
I think of all the times I've taken a plane in my life there was major delay twice - and one was at the other end of world, so a single time starting from here.
And no, I'm not one to regularly fly (and I hate to do it) but if you for example take Munich - Berlin or Munich - Hamburg, if I need to be there in the morning I'd need to take a train the day before and pay for a night in the hotel, or I fly in the morning. Proper night trains would solve that but then it might still be a wasted evening in a hotel room whereas I have no problem getting up at 4 am and catch a plane at 7.
For clarity: while part of my story doesn't apply for "train rides of 2.5h" the gist is the same. If I don't trust that the 6:30 train will make me arrive on time at 9:00 I'd need to take one at 5:30 or 4:30.
Also I fully support this ban. I'm just not buying the time+stress argument.