Yes, you didn't care about the top of the draft board, which is a leak as Doncic was a generational player (which is what most fans thought Simmons was). However the 2 picks you had before him are just average in today's NBA
IIRC, the Sixers traded a future 1st pick (from the Fultz trade) went to the Celtics, which went to the Cavs. It wouldn't have been hard to trade up for Doncic.
I guess you don't see why your hypothetical isn't really relevant. You are asking who the Sixers would swap for Simmons in a 3 year draft span. I am saying that the Sixers could have gotten much more value by trading the Simmons pick at the time of the draft.
You can't look at this after the fact and ask this question. It is the entire reason why I argued against trading up for Fultz. Boston didn't see him as a generational 1st overall pick and the Sixers shouldn't have either. However, the Sixers thought that Simmons was (which was not unfounded).
As far as what Bagley and Ayton have to do with your question.... they were in the same draft as Doncic (and judging by you previous comments, you had rated higher). You listed Doncic, but not Ayton and Bagley. In other words, you are cherry picking after the fact.
If you want to play this game, then Jokic, Embiid, and Simmons win multiple titles. You could remove Simmons from that statement and come to the same conclusion.
The big takeaway should be that the 1st overall pick has much more value before the draft than after (see the Sixers-Celtics trade). If you want to say who we would swap Simmons for years after the draft (and spanning multiple drafts), then you are using hindsight
The Simmons pick is worth much more than Simmons current value, which was my entire point.