Like Perry Mason, Columbo never seems to go away. I checked imdb.com and there have been Columbo TV shows and TV movies in the 60s, 70s, 80s, 90s, and 00s.
I must point out that Trek has been in FIVE decades, not just four.
60s - original series run
70s - movie
80s - new series, movies
90s - additional series, movies
2000s - yet another new series, movies
Yes, it hasn’t been quite 40 yrs yet (1966 - 2005), but it has been in five different decades as new programming, not just reruns.
Of course, this is only valid if you consider the franchise as a continuation of the original series. If not accepting franchising, then it’s only four decades for the original crew (as in your OP).
I hadn’t seen the '93 reunion, but the imdb lists everyone as playing ‘themselves’ so it’s presumably just a cast reunion.
Since that’s been killed on a technicality, how about Scooby-Doo. The original Scooby Doo Where Are You? hit the air in 1968. It played under various titles into the '80s (for instance The Scooby and He-Who-Shall-Remain-Nameless Puppy Hour in 1982). In the 1990s and 2000s they had two live action movies and a ton of direct to video animated features. They also had a couple of TV projects in this time including *The Scooby Doo Project * in 1999 and What’s New Scooby Doo? in 2002. As for continuity, according the imdb, Frank Welker, who provided Freddie’s voice in the original series, was still doing him in the last two shows.