I don't see Alphabet share price changing much just because of SpaceX being valued 2T instead of lets say 1T (being extremely generous). In fact this deal will hurt their profits, which is more likely to hurt Alphabet stock price than the valuation of an asset that they hold.

I’m not saying it will change much for most investors, rather that even 0.1% could in theory be worth quite a bit to a few people depending on how their incentives are structured.