A little piece highlighting price inflation from Hagerty's own site in 2021;
The Miura is not only Lamborghini's most beloved model, it's also well known as the OG supercar. That isn't going to change.
www.hagerty.com
Miuras had a big price surge during the first half of the 2010s [...]
The median condition-#2 value today is $1.2M, while a decade ago it was $367,000. From 2011–16, the median Miura price was up 167 percent, with early cars up over 200 percent.
Activity has been quieter lately but has generally trended upward,
with a 22 percent overall gain from 2016 to today [...] with the Jalpa, Diablo, Uracco, and LM002 up from 35 to 55 percent
So you have a real-life example of a car tripling in value over a five year period, according to the company that wants to provide that input to GT for a game that has a life cycle of approximately five years.
So if there is anything to be suggested by the data here, it's that if you want those cars, splash your cash early, otherwise you might be spending twice as much later for the same car before Gran Turismo 8 is ready.