While his skillful de-fanging of Robert Moses was indeed salutary, Moses was on the way down after 1960. The "World's Fair" in 1964, Jane Jacobs, and some politically dunder-headed projects that alienated more powerful voters than the poor people he was used to pushing around were all undermining his power and ability to push his projects through. It was only a matter of time before he was through
Um, he may have made more enemies, but the sort of rotating bond tricks he used to maintain complete control of Triborough didn't care about public opinion. No matter how unpopular he got, he would have remained safely ensconced in power (at least those portions of it that were most important and damaging), were it not for Nelson basically colluding with his banker brother David to make sure that he wouldn't be able to fall back on them. It was most certainly
not "only a matter of time".