I see why steam doesn't let people inherit a account and why they don't let people chose what features they use.

The inheritance is likely a legal issue with the license, officially they don't let you do it, but just logging in changing the account email and taking it will nither be noticed nor do they care.

And the features is likely because they have running costs, the small stuff like cloud save and community cost them almost nothing, what is costly is the games distribution itself and that's what they get the money for (also the advertising on the Front page). You need to send all the data from a server as close as possible to the user downloading it, steam operates in almost any country in the world. Its a huge amount of data they need to store, backup, secure and transmit, they do cut their share after a certain amount of copys are sold because they are then in the plus with less money, but they also pay for all the free games, all the mods and all the other stuff.

publishing on steam costs nothing, they just take a share, and thats a fair share in my opinion, when you don't sell, steam gets nothing and eats the costs, when you sell they gain from it as well and probability recommend people your game that are willing to buy it.