I can't help but wonder if this chicken-and-the-egg problem prevents getting the ball rolling. Nobody wants to commit to adoption if they're not confident it will scale, and nobody wants to scale if there isn't adoption driving it.

I would not say nobody, I would more say many will wait to use until they will be confident it will scale, like many waited for ETF to be confident it will not die or censored by govt. Only few will see it long term, and embrace the slow development, and they are the ones will obtain more value from it.