The problem with your your complaint, as much as I actually agree with you is that some of those races are part of different race categories. I’d love to see 24hrs of Daytona on the WEC where it belongs, but its part of what is/was GrandAM, same for Nurburgring and Sebring. I’d love to see those 3 at least play some part in the WEC, not sure it’s events single unless other racing series fold.
There is also the fact to consider that 24hr racing is expensive and a major strain for the teams, having 1 or 2 races is fine but not a bulk of the series. WEC is trying establish itself, for now it needs teams to compete so allowing races which will be cheaper to run wont scare them off.