It's most likely as our understanding of the systems and the underlying physics have changed, so have the terminologies.
There was also the push for international standardisation of units. This probably helped push terms inline with the original discoverers terms, or were "rebranded" to honour the original/significant discoverers (or for politics or whatever).

Some terms will still be used due to legacy, because it's not worth trying to change it, or because the application is more inline with the original discovery.
The more modern terms probably refer to an improved design or different application of the same principle.
Eg a rheostat only has 2 terminals and works as a plain variable resistor, often built to handle higher power scenarios. A potentiometer uses 3 terminals and is often built for lower power scenarios.

While capacitor and condenser are the same thing, capacitor is likely more popular as it relates to it's SI unit. And it's SI unit describes what it does, It has capacity to store charge.

Things like valves Vs tubes. Tube describes what it is: a high vacuum tube. A valve describes what it does: varies the electricity flowing through it.
However, not all valves are vacuum tubes, some can be gas filled. And not all vacuum tubes are valves, for example television tubes.

A lot of this comes from multiple people developing similar things based on similar premises and applications, however all being slightly different. At the end of the day, the underlying physics is immutable, just the implementation and application changes.
And there was little-to-no communication between them, so people close to each discoverers would have used their implementation.
Sorta like Apple OSX Vs Windows. They are both desktop environment computers. But they do it in different ways to achieve the same result.
And then, all of these really useful technologies became standardised (or a clear "winner" emerged), and the terminology also became standardised.
All of which results in terms dropping out of favour