The problem with this whole discussion is that T1 came to MTGO in the last years. Both the printing of absurd cards for TX strategies (first Pyromancer dominating the format, then Mentor) and Shops and the advent of total information and transparency lead to a homogenization of the format. I think this would have happened anyway, even if some cards wouldn't exist and even if some archetypes would be different, just because MTGO changed the whole approach to data we had before.
I can't really comment on the time before T1 came to MTGO but I would guess that it developed way slower and that previous tier 1 decks often needed longer to break through. With MTGO these kind of things become apparent within a small frame of maybe a few weeks.
The main problem is not MTGO, though. Wotc just printed a high number of degenerate cards in the last few years, and T1, with the unability to outright ban a card, became the most susceptible for power creep. Blue, always a good color, became so much more stronger and aggressive, while the other colors hardly got anything (Mentor is blue with the restriction of not going into Force). On the other hand, colorless, which wasn't even considered a color before, suddenly became a real force. And then another artifact block came along, which always means a few more toys for Shops. The development of their game design just shits on T1 and that is a big problem.
Actually I would even argue that Wotc kinda maneuvered the format into the worst possible dead end; not just with all the latest printings but also with the restrictions. They kinda forced a TX vs Shops Aggro format on us. Sadly, this is just another byproduct of T1 coming to MTGO and the hype that the VSL created.
What happened to the other archetypes though? Ok, so here is my point of view again: they are mostly flawed. Susceptible to variance. I mean yeah, Oath didn't get the same cool new tools as TX got. Oath, needing more specific cards to devote its gameplan to is essentially just a worse TX deck, no matter whether it plays Mentor or Pyro. Oath is of course still a great deck and can have bombastic openings, but if it only wins 55 of its 100 games while TX wins 62 out of 100 then it is just a matter of time until people switch to the archetype that grants them a higher win % over the long run.
The same is true for a deck like Dredge. I enjoy Dredge, it just crushes and operates on a different axis than any other deck. But if also produces nongames, where you just mulligan to oblivion, or get your Bazaar wasted, Dredge one or two more times just to get stack. It's not fun gameplay and it will lead to Dredge never becoming the best in the format again, unless we get another Serum Powder one day.
Other decks just generally suffer from a too high curve. Like, I think Consecrated Sphinx is a cool card, but does it really has a place in Vintage? Chances are that it just rots in your hand the whole game.
Is there a way back? I can't really tell. The way the format is structured right now is I don't really think so. Mentor gets restricted next, I think that is certainly a given, but what will happen to Shops? I doubt they are going to restrict the namesake card and pillar of the format. Restricting a Sphere seems really dull though.
Referring to Mental Misstep, I think it is just plain wrong to advocate its restriction. Misstep takes both variance and speed out of the format and that is a good thing.