I've had a few cars I've sent out to a local shop here and they do not leave gaps. One car they did was a retint, where they removed the old 90's blue-ish tint and some gaps and when I picked it up, no gaps and it was "limo" tint.
I
do think leaving gaps is just a skill issue, or the piece of film they had was a certain size and maybe they didn't want to use a new piece
This shop charges a lot, and part of it includes removing trim and doors panels so it goes well below the door wiper/seal and all around the rear glass.
But it isn't necessarily a bad thing. If your price didn't include removing a ton of trim and panels then maybe some gaps are to be expected?
It may be a problem where they did not communicate specifically what you were going to get in exchange for the price you were paying.
Maybe the majority of their customers prefer the style they gave you and they forgot to ask you what you would prefer.
I don't know haha. Trying to look at it from both angles, customer and business without just saying someone made an error.
Sometimes it's just a failed communication