Why should they? Every company has different priorities, and it's on you as a consumer to get familiar with each company's product line before making a purchase.
Would you prefer it if all products were named "<company name> <thing>"? So in your PSU example, "Seasonic PSU"? Of course not, you would like to have more detail than that. So how about "Seasonic PSU 800W modular"? OK, that's better, but what if other consumers are interested in different product criteria? Should we just cram them all in the product name like sellers on Amazon do? That wouldn't be right either. So the best approach then is to segment your product line according to some criteria, and give different segments arbitrary names. This way customers can know what to expect, and which segment to focus on. It's important to keep this consistent, otherwise it leads to confusion, but in general it works fine IMO. I would rather have to choose between Seasonic Prime TX, Prime PX, etc., than Seasonic Pro, Pro Max, etc.