The fact that Waves Audio Ltd has bundled VST emulations endorsed by multiple pro audio brands such as:
- SSL Collection
- API Collection
- Abbey Road Collection
- etc.
It is a clear sign they rightfully to obtain a license(s) from those particular companies and the rest of dem other sound engineers e.g. Chris Lord-Alge, Manny Marroquin, Tony Maserati, etc.
You can not randomly use another person's name, trademark, or service mark to sell your product in business.
For example, you can't make a Drake VST/AU plug-in without his permission and approval from other parties involved. You will get sued by Brrrrrrrr! and Universal Music Group into oblivion.
So I'd imagine perhaps it's either Waves Audio Ltd pays a lump sum in licensing fees every year or they might have an agreement where the licensor gets paid a certain percentage for every sale—just like music royalties.