Canada

From the article:

"Some of the airframe, engine and escape system program feasibility studies [that] were done ... [revealed] some engineering challenges because of the age of the aircraft that have changed that situation, and this is why it will be retiring in 2027 instead of 2030."

https://en.wikipedia.org/wiki/2020_Kamloops_Snowbirds_crash

On May 17, 2020, a Royal Canadian Air Force Snowbirds plane crashed in Kamloops, British Columbia. One person, Captain Jennifer Casey, was killed, and the pilot was seriously injured after ejecting.[1]

After a nearly year-long investigation, it was concluded that an engine stall, caused by a bird strike was responsible for the crash.[5] Both of the occupants attempted to eject, but the report showed that Capt. Casey's ejection seat did not function properly.[6] Since the crash happened shortly after takeoff, the plane was still at a low altitude and the pilot did not have time to regain control.

...

Sounds like the planes are simply no longer safe to fly.