When you attach a name as inventor of something, it sounds as if the whole concept was borne by them, which is not true. All "inventors" and "great leaders" are only carriers of incremental change, which sometimes marks a milestone for a series of changes done by their predecessors or the context.

Steam engine concepts were already there before Jame Watt, logic by electrical circuits was already there before Shannon. People provide incremental guidance for the change, like river banks do to the flow of the river. No single part of the river brought the river upto that point.

There are many cases when the incremental change that is due to an individual inventor is very clearly defined, so it is known precisely which is the contribution beyond what was inherited from the predecessors.

For that incremental change, the name of its inventor is appropriate.

However, you are right that too frequently people fail to distinguish what was new and what was old in an invention, and they misleadingly attach the name of the inventor/discoverer to the entire big system or theory, not to the small features that are truly new.

The inventors or discoverers are frequently guilty of this themselves, by failing to properly acknowledge their sources and by making exaggerated patent claims, which nowadays are too frequently accepted by patent offices that do not perform an adequate search of prior art.

It says, "Designed by Claude Shannon" (at least now it does) - did it formally say invented or what's put the bee in your bonnet?