It’s actually much more similar to how they kept using Majel Barrett as the voice of the computer across multiple series.
And it makes sense in-universe for The Doctor to be 800 years old and still working; it’s not like they’re contriving a way for Harry Kim or Phlox to be there, much as we may want to see them again.
If you’re a crew member on the Enterprise D, you have died. Probably more than once. Between Timescape, Cause and Effect, Yesterday’s Enterprise, and All Good Things, the ENT-D has been blown to smithereens with all crew on board multiple times.
Voyager did this too, but far fewer times that I recall.