The problem is that none of the 3 teams that have been named by different sources as "frontrunners" to land Lillard are likely to have FRPs worth anything in the next few years. Outside of the 21-22 season Lillard has always played 66 games or more and would likely have last season as well if the Blazers hadn't shut him down. And even in 21-22 none of his injuries were long term concerns.
So you add a 33 year old Lillard to a Boston core of Brown, Tatum, and Porzingis, or a Toronto core of likely 2 out of Barnes, OG, and Pascal plus Poeltl or a Heat core of Butler and Bam - which one of those is going to have anything but a FRP in the mid to late 20's for the next four or five seasons? You'd essentially have to hope for injuries if you're Portland.
But this is exactly why Portland should have traded Dame before he publicly asked to be traded. The Blazers would have had more leverage and got better offers and as a side benefit you keep Dame's legacy intact with Portland fans.