An auction house is fundementally different to a 24/7 online auction. In an auction house all buyers are assembled at a particular time when everything is sold. With an online auction items end at all times of day or night, so to expect most potential buyers to be there at "hammerfall" is unrealistic. Hence the "tender' format.

The current system is well known, and as long as you know how it works then fine for all.

The use of the 'auction" format is fading compared to how it used to be as more and more buyers are convience buyers, who dont want to wait around for a week for a maybe win, maybe loose, item. That novelty has worn off for many.