That's... not really an argument. Of course everyone has to act pragmatically; we wouldn't even be able to think if we didn't. But that's quite different from establishing the validity of the principle itself.
Well, it doesn't establish that induction is always valid, so I guess we might not really be disagreeing. But, pragmatically, everyone basically has to assume that it usually works, or is likely to work in whatever the particular case is. I think it's a good enough heuristic to be called a rational principle that people already have down.
I was just wondering. Human minds are messed up in 1001 ways, but are there a few rational principles that most people already have down? Of course, the answers to this question are probably so extremely obvious that I haven't even considered them. But I ask all the same.