Same applies to BSL and similar. Not being able to compete with the project owners is much less restrictive, for me, than AGPL/GPL.
And of course the third party can compete on price, they don't have to develop the actual software they're selling!
Without competition, they are free to charge any rent they like for it.
If you think that the person that originally wrote Redis or Elastic should have an exclusive license to charge people to use that software, that's a totally valid opinion and a totally valid licensing/business model. However, it has nothing to do with open source software.
BSL and GPL code are probably never mixing since they prohibit each other. This creates friction in GPL world and tends to produce incidents line this [1] out of thin air.