If it wasn't for "open source mentality", the internet would have ossified in the 90s. People wouldn't be able to put up all the interesting individual sites that they do, and there'd be only a few major companies that could provide hosting. So many of the things we take for granted have grown out of side-projects that would never have taken off with a high barrier to entry that is commercial-grade software. Certainly the web wouldn't be as advanced as it is now, as 'vested interests' would have won far more frequently than 'pragmatism'. "Which DB do you use? MSSQL or Oracle?" - RethinkDB would never have gotten off the ground.
> because the open-source developer tools market is one of the worst markets one could possibly end up in
Well, a production-quality database isn't really a 'developer tool', but even then, there are dev tools that have carved out a comfortable niche for themselves, such as SublimeText.
The problem isn't the open source mentality, the problem for RethinkDB was competing in a saturated market with a major competitor who had already won a lot of mindshare and gained a lot of traction.
> because the open-source developer tools market is one of the worst markets one could possibly end up in
Well, a production-quality database isn't really a 'developer tool', but even then, there are dev tools that have carved out a comfortable niche for themselves, such as SublimeText.
The problem isn't the open source mentality, the problem for RethinkDB was competing in a saturated market with a major competitor who had already won a lot of mindshare and gained a lot of traction.