No, they don't just use the software because it "feels familiar". Everyone is acting in their best interests, nobody is going to sit in a sub-optimal position just because they can't be bothered. If you use non-standard software, then everyone else will reject your proposed blocks.

The only way you can use the concept of Schelling point is to explain why so many people use Bitcoin rather than Litecoin or another slightly-tweaked variant. Much like the example in the article, if you ask anyone to pick a cryptocurrency to pay with, they are likely to say Bitcoin because it is familiar.