That is only true in the simplest scenario of taking a train on a flexible ticket and without any transfers.
As soon as you have transfers in the mix (as you often would if travelling longer distances) or stricter tickets, not making it to the train is usually a really bad option.
Can we at least agree that for better or worse, train stations are typically smaller, faster to navigate, and missing significant security bottlenecks that cause significant delays in accessing airplanes?
It’s also true of transfers (changes) on routine journeys in most of the world I would have thought. Because almost all services are regular. It is the arrival time at your destination you build time into, then you work backwards, right?
IMO booking strict tickets (e.g. booking a seat) makes sense on only a small handful of routes in the UK, for example, and may even result in you being offered fewer possible options.
There are some quite infrequent routes in rural areas where missing a connection is a bigger problem, but on those journeys I tend to consider my arrival time at that connection to be the starting point.
For the train journeys I take it’s pretty normal to have two or three changes, often including a trip across London. I rarely get into a situation where missing a train is a problem, because of the nature of the train timings. The last time I was delayed significantly was due to catastrophic flooding.
The fundamental difference between air travel and train travel is that missed flights have to be rescheduled. Missed train journeys, not so much. In the UK if you miss the train you had booked a seat on, you can usually still travel on another one if it's a travel period covered by your ticket (e.g. only travelling at peak with a peak ticket). You just don't get a seat guarantee.
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An aside:
Train travel is a flow state/mindset thing. Get one train earlier than you strictly need, find something to do while you're on the train (bonus points for something you can still do while standing). And then try to remember your journey is no more important than anyone else's, maybe a lot less, and you have no more right to timeliness or expedience than anyone else... maybe a lot less. As long as your journey is progressing, things are fine.
The other week I was on a train and there was a thirty-something woman and her parents, taking up a lot of space around me and chatting incessantly and being silly, and I was just about to performatively put my headphones on (the rudest you're allowed to get when people are crossing the threshold of appropriate levels of noise) when it dawned on me that they were being silly because this thirtysomething woman was going to a hospital to find out whether her tumour had returned. And then it dawned on me from their route-planning discussion which hospital it likely was, and what that likely meant for her, and I hugged myself and read my book.
I was on a train about 15 years ago, on a local journey, that was held outside a station about three quarters of a mile from where I worked. Stuck for three hours on a cold train in winter with no working toilet.
About an hour and a half in, people were getting very angry, until a member of the rail staff walked the line back to the train, boarded, and went through the carriage explaining carefully but respectfully exactly why the train couldn't get into the station and why we couldn't all walk along the track. Once they knew why, the angry people started chatting and sharing snacks and talking to strangers like they were old friends for whom life had suddenly become too short to be angry.
