I agree with you but this should impact more the main stream second hand car market than the "luxury / sport" market in my opinion. I have been looking at two cars that I really like, the 997 and Maserati GTS for the last 6-12 months, both have increased very strongly in price, especially the 997 from what I have seen. For me, it is either because these cars were undervalued before (it was a lot of car for app. £25k) or there is currently a small bubble for these cars due to summer and spare cash after lockdown. Which assumption is correct, I am not sure? I am very tempted to make a move to buy one although might be worth waiting for 6 months...
All prestige/sports cars are generally cheaper in winter no matter what the market as a whole is doing. So if you want to grab a potentially cheaper car, then winter might save you a little especially as the economy and average Joe are likely to struggle post covid.
However, there is also less to choose from, as a lot of owners sorn them and put them away over the winter months. And if they were planning on selling might wait for spring to get a better price.
I think a lot of owners are considering selling now, as due to this market rise, they can potentially have had a year or two free motoring, and it's not often that happens when talking about these sorts of cars.
To be honest though, if buying this sort of car, a few £K saved here or there at purchase can easily be eaten up by servicing or unexpected maintenance.
Decide what you want and go for it. Life is short, and if like me, having a car like this is was a dream move, then at least you've done it.
Who's to say what your personal circumstances, health or finances will be like in 6 months? Would you rather have experienced the joy of owning one and lost a a few £k, or look back and wished you'd have owned one while you could?