The dynamics of open source development are very different from commercial ventures. For example, Mastodon is basically developed by a single person with a few contributors. Yet, from user perspective it's superior to Twitter in many ways which is a company that used to have around 3k employees. The fact that Unity is a big company that has a lot of money doesn't directly translate into doing much higher quality development over Godot. It's a more polished product right now, but even a few hundred thousand can make a huge difference for Godot because that would mean full time development for at least a year.