If Barry succeeds in his plan, he may be able to keep his powers, but what about the others? Unless Reverse-Flash is restored in some way, Barry may become the only speedster on Prime-Earth in The Flash.
West could not remain Kid Flash, Jay Garrick, who will exist after the crisis, he would probably lose his powers. If this happens, Barry could lose two of his most trusted allies in The Flash.
If this is the case, then The Flash may have significantly fewer speedsters, which would help the show go back to the days when Barry Allen was the only speedster in the Arrowverse.
Season 6 of The Flash had already moved away from speedy characters but the death of the Speed Force means that The Flash could take this even further in future seasons.
Wally mentioned that when the Speed Force was alive, she could see how she connected with her children and other people with the Speed Force. The death of Speed Force in The Flash puts an end to all that.