This descending-fifth motion is definitely referring to the root motion, not the bass motion. With that said, your I–vi–IV–V progression is very common, but not in these inversions.

Depending on what style you're in, creating bass motion of a descending fifth (like you have) can result in "illegal" uses of six-four chords, non-resolved tendency tones, etc.

Interestingly, trained ears tend to focus on the bass. This would mean that a trained ear very well might assume your bass is right, thus resulting in them thinking something is wrong with the upper voices. In other words, even though the real "error" is the bass, trained ears may think the error is in the upper voices because we tend to assume the bass is correct.

Lastly, even though your example was just for illustrative purposes, doublecheck your vi and IV chords: the vi is missing the root (!) and the IV is missing the third.

The suggestion of descending-fifth motion is definitely referring to the root motion, not the bass motion. Your I–vi–IV–V progression is very common, but not in these inversions.

Depending on what style you're in, creating bass motion of a descending fifth (like you have) can result in "illegal" uses of six-four chords, non-resolved tendency tones, etc.

Interestingly, trained ears tend to focus on the bass. This would mean that a trained ear very well might assume your bass is right, thus resulting in them thinking something is wrong with the upper voices. In other words, even though the real "error" is the bass, trained ears may think the error is in the upper voices because we tend to assume the bass is correct.

Lastly, even though your example was just for illustrative purposes, doublecheck your vi and IV chords: the vi is missing the root (!) and the IV is missing the third.