This cannot possibly be true.
Yes, legacy software is a big deal for Windows, but legacy software is not literally clicking buttons in these old archaic menus.
A shim or compatibility layer should have been added, and all settings migrated into the single Settings menu. There is no reason to have multiple versions of the same thing... especially when one of them is permanently hobbled and users have to guess which version exposes the buttons they need.
How long has Win10 existed? Nobody smart at Microsoft has figured out how to unify Settings and Control Panel in all that time? Literally means they have not tried. All of these things hack on the registry when you get down to it...
What probably actually happened was someone found out all the deeply nested menus and ad-hoc buttons in Control Panel didn't cleanly port into their "elegant" Settings app, so they just stopped there and left it to rot.
We want to look beautiful more than we want to be functional, apparently.