I've said it before I'll take 250 extra special cars even over semi-premium and standards honestly.
What makes them "extra special" to warrant spending more effort on them? We already have 400, so presumably there is something lacking in the existing Premiums.
This 1000 cars crap got old fast now that I'm looking back at it people like the idea of 1000 cars, but most of those cars barely get used.
Any data to back that up? The point is that any one (average, probably non-GTP) player might only touch a few hundred cars at most, and whilst there will be islands of overlap between those usage lists that may point to a "popular cars" list maybe two or three times the size of the average player's total car use, there will also be plenty of fringe. It's really all about that fringe, that's where the magic of "esoteric" car lists lies (esoteric but containing some hidden gem that makes one player's day; multiply that effect with the size of the car list); and it's not all about your fringe, or mine.
I'll even go back to 150 cars like GT3 in some ways less means more it would solve the duplicate problems, and give more to other companies such as Spyker, Cadillac, etc etc.
By offering fewer cars, you are conceding to having less variety. How do you do justice to the rich history of motoring with just 150 cars? This is not Need For Speed, where you absolutely positively gotta have every "hot new car" in the game, but a rather more broad, even experimental (VGT), experience. By offering the same cars as every other game (which would have to happen to condense enough enticement - marketing - into such a "short" list), you're also conceding to having less variety. The large car count frees PD from having to make that specific concession, that is: offering the exact same car list as every other bugger.
We're not talking about brands of mayonnaise here (same stuff, different label; often literally), this is more like the difference between chocolate bars (very different blend and, crucially,
choice of ingredients). Mayonnaise is mayonnaise, more or less, but everyone has a favourite chocolate bar - and that's OK. Thankfully, despite the limited range of expression in terms of ingredient choice for chocolate bars, you're not really limited for a car list in anything like the same way.