Dave.
Other than a new Fluke to check the accuracy of what vintage equipment I restore and maintain and a couple of newer soldering/rework stations, every piece of test equipment on my bench is 20 to 50 years old. Yes I could fill the bench with all the latest test equipment but for what I like to do it would be a waste. The old stuff works just fine. I suppose one of these days I will buy one of these new fangled digital scopes to play with but it's not required for what I mostly do now. Heck, until the later 1950s most service shops didn't even have or need a scope. I could get by with a meter, soldering gun, some hand tools, and a variac. The rest do make some things a little easier but I've been putting together my bench since the early 1980s so a build up of bench equipment would be expected.
As far as collecting, that's another story. As Dave said, my test equipment collection is not unlike someone else collecting vintage computers, calculators, pinball machines, cars, or whatever. It just depends on what you are interested in.
I have over 100 tube testers. Most are pre 1950. Do I use them all now? No, of course not. I use two from the 50s and 60s. I have an interest in their history and design though and keep them around as examples. Beats having them rot in someones basement, attic, or barn. Do they sit in my shop? Yes, and not many people see them. Is it a waste? I don't think so. The more interesting ones I post on the web site along with their data so others can see them and enjoy reading about their history.
There are more people into test equipment than you think. I get a constant flood of emails from people looking to restore something and looking for parts and service information. It's taken many years to build up the collection and library of service information. It's what I like to do. I gave up designing the latest digital circuit years ago. So what. Many today don't have a clue as to how a tube works. Does that mean that that knowledge will eventually be lost? I hope not. Collectors actually help preserve the technology of the past. Think about that the next time you see an old vacuum tube voltmeter at a garage sale. It may not be a Fluke but it was a great piece of test equipment.
As far as the guys buying all the latest and greatest test equipment that they probably won't use, that's their choice. Heck, I know people that spend a lot more on cars, boats, ATVs, and other crap that I'm not interested in and mostly sits in their driveway but so what. That's their money and their choice. I happen to like old test equipment.