The truth is that this likely isn't going to work out for them. Or if it does it won't be to the level of success they want. But they're obviously committed to trying and it's not really your place to tell them not so. They deserve someone who's all in while you deserve a band that can fit into the rest of your life. Personally I've taken latter hobby route over the years which is a lot of fun and it's not hard to find people who are on the same page. You can still take it seriously you just have to set your expectations accordingly.

Hell you can even still end up touring. I'm in my mid thirties now and my current band are all on the older side, youngest your age, with commitments and we're doing a couple of week a year on top of regular, but not every weekend, gigging. We're all on the same page about how much time we can give to the band and have got the experience and contacts from years of playing in them, serious and otherwise, to be able to make the most of it.

Guess my point is comptable goals are important and you've run into a couple of kids who are on the extreme end of the commitment scale. If it was a just a case of joining a younger band who wanted to tour at some point but they're all in school or uni that would be much more manageable. But we're talking about a couple of kids who have dropped out of school with the aim of doing as much touring as possible. Do you really want to be the guy in that band who couldn't commit when it, likely, doesn't work out as well as they wanted?

Keep looking, as you found being in bands is fucking amazing, you'll find people who are more compatible.