I believe Magpie is correct on Codemasters involvement.
1. This game is still published by Namco/Bandai.
2. The game as it is coming out, it will be very similar to Grid, creating a sort of overlapping which surely does not make Codies happy.
3. All productions developed this year have suffered from the Covid-19 situation, in many ways. Look at how ACC on console has been launched, and is poorly supported now.
I am not fully buying the features removal as early development decisions.
My humble theory is that, despite of what SMS keeps saying (and honestly I don't believe anymore a word of what they say), this game really gave them some troubles during the development, and it prolonged for much longer than initially expected.
Few months ago they reached a turning point where they realized that they could continue going on developing the improved full sim game (but it would have taken ages and they would have released the game AFTER the next gen consoles launch), OR they could simplify (literally, cut) many aspects of the game, and have it release BEFORE the next gen console launch, to maximize the sales.
And avoid releasing a old gen game in the next gen era.
Infact they are rushing so much, to get the end of August deadline, that even some basic features (as HDR implementation for Xbox version, or private lobbies) will be added later.
And they already candidly said that, confirming that development of this game was far from being well planned.