The biggest reason is obviously velocity but I don't think that we will ever get pitchers to lower velo or even just taking off something on some pitches.
There are ideas out that intent to force teams and pitchers to "pace" themselves (like the pitch clock or reducing roster size) but I think that won't help and cause pitchers to burn out even faster.
My idea would be the opposite. There are studies that the Japanese NBP league has well lower injury rates and while part of it that they throw slower on average also starters only pitch there once a week. There still is injury risk pitching like that but I think the extra rest lowers it some.
So why not expand rosters and allow up to 16 pitchers? That way teams could use 6 man rotations and give bullpen guys more rest.
I don't think this will eliminate all injuries but maybe it lowers the rate some.