1. Fair point, though what I said about trades still stands as I'll explain below.
2. Philly doesn't have to worry about sending matching salaries because of their cap space; I'd be willing to bet that the lure of immediate cap relief probably outweighs the benefit of taking on Wallace's expiring contract for pretty much any team that'd be in a position to trade a key player away to Philly. Even still, the CBA has depreciated the value of an expiring contract.
If Philly wants to acquire a star player, they're giving up that first rounder, with or without Wallace. If they need salary filler, they can accomplish that by signing their borderline NBA players to multiyear deals with partially or fully nonguaranteed years. See: what Cleveland and Charlotte just did this past week.
Beyond that, they don't need to even trade for an impact player - they can do what the Celtics just did and just serve as a fortunate third-party to facilitate a trade while collecting assets from desperate teams.
3. That explanation only addresses why the Celtics wouldn't do that deal, not why the Sixers would do it. The Celtics not needing the deal doesn't give the Sixers more incentive to do it; that just gives the Celtics more incentive to walk away. "I don't need to do this deal and neither do you, so take this deal, anyway" isn't a very good way to bargain.
For the record, Utah most certainly was in that position. They had about $30 million in salary committed to players who didn't come from Golden State.
4. No, this is just silly. As a New Yorker who watches the Knicks very frequently and considers himself a Knicks fan to a degree, I can tell you that Amare can't play any defense, has low BBIQ, is an offensive black hole, and is limited in regards to playing time due to questionable health; at this point in his career, he is no way, shape, or form good or reliable enough to make the Sixers "too good." He is purely a part time role player who can still show a flash of the old Amare from time to time.
Even beyond that, I think even Hinkie understand that you can't just keeping tearing down a team without trying to establish a foundation. He's gotten rid of all of his inherited long-term salary for the most part; I think this year is less about being "actively bad" and more about just playing guys who aren't good enough yet to win regularly. The fact that he was willing to trade for Jeremy Lin only further suggests that "being too good" wasn't exactly a major concern (if one at all) for him.
I understand what you're saying, but it's not in the least bit feasible. Recent history has shown that Philly can do far better than what you're saying. They have all the leverage here and they've also shown a willingness to walk away from deals that aren't sufficient (Amare, Lin). Those proposed deals were for two guys who won't even be on their books past the year and in the case of Lin, someone who has enough value to potentially be flipped by the trade deadline for more assets. They're simply just not taking on Wallace and his contract for a second rounder. It's not reasonable at all nor does it even fall in line with Hinkie's past dealings.