I'm sorry to say that the situation is worse than you described. It's not true that descriptions are misleading, they often say the truth, or they are misleading the other way around.
Take for example MemberPress, one of the most popular membership plugins. If you go to this page https://www.memberpress.com/plans/memberpress/ it says that in the business edition you have updates and support for one site only plus a staging site. That seems ok, unfortunately without the activation key the plugin's menu remains hidden and you cannot use the plugin. So they don't just limit updates, they limit the use of the plugin to one site only.

This was an example because I am using that plugin right now in a client's work but there is plenty of plugins out there that do the same thing. This is against GPL license, and it's becoming a very common practice. I'm not talking a bout a SAAS where this is legitimate, I'm talking about a standalone plugin.