There's a cost to software that always works correctly. If one of the avionics software engineers I've worked with tried to write a consumer webapp, he'd work so slowly that by the time the app was done, I wouldn't need it anymore.
When Reddit was young, I sent a couple bug reports and feature requests to spez & kn0thing. Within an hour, they had the code done and up on the live site. The cost of that was that their users did the QA, which is simply not acceptable for avionics. But I'd rather have a feature done in an hour that may or may not work than wait a month for a feature that I know will work, but is probably rendered obsolete by developments elsewhere on the web.
He means most people are not willing to pay for their web apps to be as well-specced and thoroughly tested and verified as serious software. That goes both for dotcom companies and end-users who votes with their dollars and simply don't care if a website crashes from time to time.
I am not sure of that part. I think I would like to be able to trust my software just a little more. Not working properly is NOT OK.