First, an attempt to _kill_ rehitza would show that the world is built on killing …
2nd, each yetzer has another side and eliminating the negative side will eliminate the positive. For example, when yetzer for A’Z was eliminated during BM2, so did prophecy. T’Ch tried to eliminate yetzer hara totally, but this stopped marriages, work, and egg production.
While the theory is clear, I am not sure what would be the downside of eliminating rehitza? No more shehita and surgeries? Maybe it goes to what is the motivation for rehitza – power and envy? The downside for those might be a drive for business and building communities.