What is this? A 29er tire on a Trek Marlin or something? My son's Trek Marlin hasn't been any issue with any tire I've put on it's Bontrager rims. And I have put Continentals on it.
Believe it or not, it's more likely that you aren't doing it right!
If the first side of the tire went on the rim easy enough, the second side can too. You just have to learn and practice more.
Narrower rims can be more troublesome though. They don't have enough room in the spoke channel or center of the rim where the diameter is the least. That's where you have to get the bead of the side tire you are putting on if you want to have an easy time. However with narrow rims, the tube and other side of the tire you already have on compete for that valuable space. So be sure to push them out of there as you push the unmounted side on the rim.
Since you are un-mounting the tire, then from the get go, be certain to push the entire side you are taking off into that spoke channel and everything else out of the spoke channel. Do that before you ever try to use a lever, then you won't break the lever.
When you get good at it, you can put a tire on without levers. When you are really good, you can remove a tire without levers. I can! <grin>
Do some tire manufacturers have a reputation for building tires that fit a bit loosely?
No, not that I've noticed. However there are some posts that people swear some are worse and others better, but between two people posting about the same issue, what one says is an easy tire, the other will say it's the hard tire to mount or remove.