I think there's a major difference between say, support figuring out how to implement their product, which is a you problem, their service is working fine.
And a wholly different one if they screw up and you can't talk to them about it without paying them.
The former is an incentive to self-serve and investigate yourself, the latter is an incentive for the company to provide shoddy service to people pay to resolve it.
Tiered support contracts are common in enterprise software. If the base level of service were bad, nobody would use the software, and that's clearly not the case here.
(More common is the Oracle/IBM-style approach of making your docs vague enough that you need professional services to actually integrate the product).
A free level of support that requires answering within of 14 days to any issues via email, letter, or phone, and providing an address that a letter can be sent to, is required by law in the entire EU for any paid services.
And a wholly different one if they screw up and you can't talk to them about it without paying them.
The former is an incentive to self-serve and investigate yourself, the latter is an incentive for the company to provide shoddy service to people pay to resolve it.