Well, one thing is that what is offered now and what is offered when Lakers say "ok, this is really it we're moving on to other things" are different things.
I don't expect Spurs to tank, and thus I'd be surprised if they valued a Laker 1 over Kuzma---that would be a significant mistake in my book. Even just on asset value, it's a mistake. So I guess i see their asks differently than you do. I think it's possible they want a several-year-out unprotected 1, but I think they also realize the Lakers that far out are not at all a sure thing to be a lottery team too.
I agree with others than Randle is a piece SA might find interesting, and is lower-cost from Lakers perspective.