Cardano is actually more subtle than that: it simultaneously tanked because of the whole BTC thing but it also got good (and clearly carefully coordinated) press as a “greener” alternative to BTC as a result of the self-same crash, which boosted its price.
I think people are switching to Cardano because it has lower environmental impact (proof of stake) than others. The Tesla announcement was about the environmental cost of Bitcoin after all.
I'd say this observation might be correct, on the basis that the Tesla announcement also sent the lesser-known NANO currency up by about 60-80%, which uses PoS as well.