To be fair, they were both very good at Brighton. Overpriced of course but they impressed.
I am not sure I would really judge them at Chelsea. I think they'd both be decent at a better run, non-basket case club.
However, you're right - I guess in the end, we can only judge them on the reality and the reality is they're playing poorly for their club. Cucurella showed he can perform in a different environment for Spain this summer (though it's always risky to go by international tournaments). I just feel both would look better at a different club.