It was the locals who decided that it was worth the extra hassle and expense (and that doing the same thing at St. Margrethen wasn't).

There was probably a referendum at some point. :)

I am not sure whether the stats are comparable, but I read somewhere that about half of Deutsche Bahn trains are late into Basel (and there are many trains a day). While I don't know this for a fact, it wouldn't surpise me if patterns of delays are relatively predictable and can be planned for.

There was some talk about just ending those routes at Basel at some far-away point in the future, but I'm not sure if that's something that's been decided.