I haven't read any Stephenson, and I don't know anything about his stuff, so I'm going in blind.
As for OPM, Kay is pretty sanguine, actually. The material might be a little scary, but ignoring isn't going to make it go away. One comes away with a sense of despair, but with a shimmer of hope in the silver lining, too. The takeaway message of the book is that there are a lot of people in finance who would like to do right by their customers, but that currently, the economics favor more trading, and more focus on tomorrow than rational trading and more focus on distant time horizons. The only policy solutions he advocates are ring fencing deposits from investments, and the Tobin tax or something similar. Absent its adoption, whose chances are nil right now, Kay thinks that what the system needs is a return to retail customers' outcomes as their primary endpoint. All in all the book pissed me off, since it made me relive 2008, but it is a very worthwhile read. Highly recommend.