Obviously. But why was seemingly everything contingent on what the Raptors wanted? Diminished value or not, the Spurs were the ones trading the premiere player.
The Raptors needed a C anyway (though more of a depth one) and ended up signing a somewhat similar one in Monroe. There's no reason to think this would have been a deal breaker.
And if Leonard stays, the trade looks even worse on the Spurs. The Raptors had no leverage once word had gotten out of the discussions being serious, since it was obvious DeRozan would be the centerpiece of the return. At that point, they needed to close the deal.
Talent wise, particularly given the cir stances, the Spurs did well to get a top 30 player, a lottery pick and another 1st . . . but fit wise, they cemented themselves as an archaic outfit and possible treadmill team and gave the Raptors a virtually ideal modern team (minus a play making C, that can switch).