[hn_throwaway_69]

It's a paid product with a team who need to earn a living wage. It's not like VS Code where the team is bankrolled by a big organisation making its money on other proprietary products.

In light of the above, it makes sense for it to be proprietary and closed source.

Were it open source, people could fork it and distribute it freely, with no remuneration going back to the developers. I doubt the developers could offer any other incentive such as support to make up the shortfall.

"Source available" licences where the user is prohibited from providing the software to others doesn't meet the FSF's definition of freedom, so even that wouldn't please everyone.