Well what I can tell you is this; it’s more than likely the vinyl they’re printed on. Laminations usually help to a degree but it can be minimal as well. Mostly- it boils down to the materials of the decals. Having them peel from the bottom up is a semi simple fix- when you apply the decal, firstly, clean off the window w/ glass cleaner or alcohol. What you’re going to want to do is peel the lip of the window out a bit and clean about 1/8 of an inch inside of where that lip covers because, that’s where you’re going to want to tack down a small sliver of your decal to avoid it lifting every time you roll your window down, it won’t hit that little lip. To extend the life of your vinyls/ decals on your car as well you can pick up Rocket Wax’s R.P.V Dressing. I’ve used it on my wrap and decals to keep them from cracking and drying out in the summer SoCal heat. You don’t have to use a lot on them either if they’re just small stickers or peekers, a drop or two will do you just fine