Last year, there were rumblings we could trade for George AND Sign Hayward to effectively have a Big 4 of Isaiah/Hayward/George/Horford.
But the main problem in that was that George was a rental and there was no guarantee he'd stay here after the 1 year, and so Ainge would not give up any premium assets for him I believe (at least that's what reports say). If he was willing to, then I think we would have gotten him (because at the time, NO ONE expected Oladipo to become what he did with IND). The logic was that it'd suck if we brought in George for one year (trading a premium asset or two) and then he bolts the next year to LAL. OKC currently could see that happening to them.
This isn't that much different from Kawhi who is a rental right now who very well could just bolt to LAL the year after.
Ainge IS NOT trading Jaylen Brown for a rental, period. If there was some way to do it with a Smart S&T, (rental) Morris + 2-3 Picks (or 1-2 picks + rental Rozier), then Ainge might do it. Otherwise, I don't think BOS makes much of an offer for Kawhi truthfully. We stand relatively pat which is perfectly fine by me (hopefully bringing back Smart, Baynes and drafting someone decent at #27).
IMO, best case scenario is him going to the Clippers. Maybe they offer #12, #13, Johnson, Beverley and Harris to get it done, and that's a pretty good package overall. That keeps him away from LAL and PHI.
And the poll with the 4 trade ideas above, those are probably the four only possible trades we could do for Kawhi (I'm assuming Horford, Hayward and Tatum are understandably untouchable in this, so...).