2 per decade, that's not insignificant. I don't see the need for planes to be flying in tight formation for spectators. The margin of error is so low. With computers I don't see how you could even have many accidents now. But these planes are ancient hunks of junk.
That's what the military does, it isn't airline flying and just about every modern airforce has a display team. These aircraft are not junk, they are extremely well maintained. They allow the Snowbirds to do a routine that is unique to jet military teams. They will need replacing some day but USAF is still flying updated B52's that are older than the Tutors and plan on keeping them in service until the 2050's. There are WW2 warbirds built in the forties flying at airshows.
The USAF Thunderbirds and the Blue Angels have both lost 13 pilots since 1970.
The Snowbirds have a better safety record than either of them.