It depends on what the parachutes are used for. If I'm airdropping food, and I can airdrop with 100% reliability for $1000 per unit food, or with 80% reliabilit

It depends on what the parachutes are used for. If I'm airdropping food, and I can airdrop with 100% reliability for $1000 per unit food, or with 80% reliability for $100 per unit food, guess which I'll take? There's a market for cheap, fast, easy, and good-enough reliability. There are plenty of data stores like redis or memcached which promise and deliver exactly that, with known parameters, and they're awesome. I'm building an application right now where long-term data integrity doesn't matter too much (a dashboard will be down for a few minutes if we lost data), and they're the right way to go. What I do grapple with is that MongoDB is none of those. When I've seen it used in projects, it was slow, hard, and expensive. Because Mongo overpromises, it's hard to tell what its real limits are. You're quite likely to step on a landmine where something was promised but didn't come through. When that happens, you either have a huge amount of deep voodoo debugging, or perhaps it's a problem without a solution. That's almost always a lot more expensive than designing around psql in the first place. And it's not particularly fast either.