The 6ers fans are so delusional right now when it comes to this offseason that it has to be coming from somewhere. Everybody over there from waht I've seen is talking themselves into actually being players for Bron (no way), Paul George (absolutely no way), or a Kawhi trade (a guy they'd have to trade for when there are a minimum of 3 other teams in the league [us, LAL, Mil] who can probably put together a more appealing offer than what Philly would be willing to give to get him).
All of this is a long way of saying I think if they signed Smart to a giant, cap-eating offer sheet, their fans would revolt. They have a WAY, WAAAAYYYYYY higher opinion of where they are in terms of contending and being viewed in the league than what reality states.