joseph….the problem with your quote is that you see “ma-aseh bechol jom” and on every daf of gemoro that the tannaim and amoraim and rishonim, DID dispute the words of their predecessors all the tiem.
if the gemoro you quote meant that we could never question anything of a previous generation, then how come there are machlokes ALL the time?
In fact, the gemoro you qoute does not deal with opinions and piskei halacha, it deals with gadlus and having the tefillas accepted.