This is a common problem in Silicon Valley: building platforms, instead of focusing on solving valuable problems.
But instead let's focus on an important problem many humans have(to a lesser or greater degree) - bad memory. And it's very valuable - employers would be happy for better employees that do less errors, and people would really appreciate better memory. So there's money in this.
But if you think about it - the smartwatch could be a great memory aid[1].
And i've seen some research showing smart watch based checklists could help nurses reduce error rates. And another research app that could help people with Alzheimer.
But nothing on the market. And zero effort from the big guys to work on that specific problem. And thus we get the smartwatch - a useless gadget that solves tiny insignificant problems. And thus it failed.
And it's the same thing with the IOT. Solve the elderly fall detection problem, well. Solve the security problem, well. Find a few more key problems like this and solve them. This will make your solution a must have. Than you could build a good platform and convince others to join(assuming you're not too greedy).
And as for the quality problem you mentioned? There are ways to create platforms that guarantee quality. For example, a rust based microcontorller OS, that severly limits what apps can do.
[1]Think of having voice activated checklists[1](to reduce errors at your job or home) that are always there. Or after having an important conversation , saying "remember", and the watch remembers. And of course voice activated search. And context dependent search(using something like a high-accuracy location detection) to better narrow search and effectively present contextual info. Or use knowledge from psychology about how our memory works,