True, you need trusted third parties. But right now, we have far too many of those. I'm not sure if blockchain would ever completely eliminate third parties entirely - you always have the system itself and the components of said system between users. What it does eliminate is layer upon layer of middlemen where the problems currently lurk. And given the way the blockchain is designed, those necessary third parties would find it difficult to seize total control of the processes. For those reasons alone it's worth exploring I'd think.
We're in the early stages still and, yes, the space is rife with grifters and solutions for non-problems. I think all that shakes out as it matures. Like the internet bubble in the early 90s. Lots of people declared it dead when it burst, assumed it was for nothing but grifters, and a few years later we see the internet giants (Amazon, Google, etc.) rise.
That, of course, has created myriad problems as well (and, arguably, participated in the consolidation of wealth that led to cryptocurrency).
We'll likely witness the same events in the crypto space - bubbles bursting, legacy institutions rushing in to attempt a take over...one could argue that's been happening lately. Only I think the blockchain will prove more resilient than the current paradigm where the massive wealth consolidation seems irreversible.
Even if enough regulations can be established to dismantle the corporate monopolies now (unlikely given the compromised nature of our "democracies" at the moment and their enslavement to the moneyed few), there is no means of fairly distributing the gains without a restructuring of finance altogether. Crypto at least represents an attempt at that effort.