These old warbirds are slowly disappearing. Just last month we lost two P-51’s. I attribute a bunch of it to today’s pilots not being qualified to fly them. Not in the sense of having the ability but they do not fly them enough to keep proficient. At least 1 hr./wk. is probably the minimum needed to maintain proficiency.
There are of course some crashes that are the result of mechanical issues but more often than not it is pilot error as well as pilots not versed enough in emergency procedures.
You make a good point.
These planes are not inexpensive to fly, they guzzle fuel and maintenance has to to a big cost.