The limit of the garage cars are 2.000 cars if i remember well from what
@Chikane_GTR wrote before couple of months.
He reached that level and needed to sell some in order to buy others in their place.
Personally took me around 6 and half months to buy all the cars playing EVERY single day at least 2-3 Griding races and at days off and vacation more than 3 .
Using easy level took me 19 hours to unlock level 39 where grinding races unlocked and with the best possible economy since i was aware of what's going on reading all the stuff here about gt7 .
I bought the game with ps5 together last March when ps5 was start to be available for the public without the scalpers price😁 .
A logical ( short of ) amount of time needed and is about 6-7 months to acquire all cars of the game .
Older players that had the game in early stages might done it in a shorter period cause they took advantage of some glitches during the first period and Hagerty prices wasn't so insane as is now days.
The one third of them are " useless " and mostly are VGT'S especially the electric ones and many of the Hagerty's list that you can't run them anywhere since there's no appropriate races to put them unless you improvise.
My opinion is that ONLY in gt7 - cause of his structure - rise the need to collect all cars , it's the way they build it and with the ridiculous Hagerty overpriced connection and appearance in rotation.
Note that credits from money you pay for ,are unlimited , but credits from the game are only 100 millions and always they giving us reasons to spend them somewhere 😂 .
Things like expensive swaps, different colours to duplicate expensive Hagerty's cars etc.etc.