Well, In my opinion this is exactly how Open Source is suppose to work - you get benefit of collaboration on writing the code and promoting your software by broad community, you give more value to your customers because they have a choice of vendors rather than single vendor lockin but also as you give up on having monopoly it is well possible someone else will be making more money than you on your product.
You mention Elastic - do not forget it was built on top of Lucene, capturing most of the value in that project.
It DOES very much impact users because users increasingly want DBaaS experience and if the only one you can get is through MongoDB or MongoDB authorized partnershp it is really no different than proprietary software.
In any case I agree for certain users SSPL is just a good as Open Source, same however can be said about Proprietary Software - some who just "buy subscription" do not care.
You mention Elastic - do not forget it was built on top of Lucene, capturing most of the value in that project.
It DOES very much impact users because users increasingly want DBaaS experience and if the only one you can get is through MongoDB or MongoDB authorized partnershp it is really no different than proprietary software.
In any case I agree for certain users SSPL is just a good as Open Source, same however can be said about Proprietary Software - some who just "buy subscription" do not care.