Ah, but the other guys have BEEN in government and at least had a shot, so we know they can’t do squat. Moreover, none of them have ever held a gig outside government. Sorry, enough of that.
The Senate itself is an ossified body that places far too much emphasis on seniority for a junior Senator like Rubio or Cruz to have the power to do much. And then there's the issue of having a Democrat President who vetoes anything conservative anyway. It's the position that limited their authority, not anything they did or didn't do.
Trump wouldn't have been able to do anything more in their place. And that's why both Cruz and Rubio are running for the Presidency, because it is impossible for a single junior Senator to get much done.