A watermark? I haven't built anything with unity but all I can find is as long as you make less than $100k/year you can build and release with free with just a required splash screen.
And even if unity suddenly does become an overpriced piece of junk, there's other game engines including a good number of GPL and MIT licensed free ones.
For the hypothetical 10 man team looking to break into the market with no money to spare for a big license, there are alternatives. And if they refuse to do without the extra pretty unreal rendering provides, then they probably lack the ability to compromise on other aspects of their vision and are pretty much doomed to fail.
Unreal's licensing scheme looks like nothing more than a way to squeeze some cash out of students looking to learn the engine before applying to a big company.
That and court small to mid sized studios that have the resources to actually utilize the unreal pretties, and hopefully score a popular enough release to afford a real license and cut down the royalties.