OK, I'll type slower.
Without Robinson and/or Duncan since 1989, the Spurs wouldn't have been anything special, even with Popovich. I think modern NBA history shows you can't be successful consistently without a dominant big man unless you have Michael Jordan on your team.... no matter who your coach is. You can argue the ebbs and flows of team success are meant to be mitigated by draft position, so I won't debate the David Robinson acquisition. The Spurs were awful for several years before he arrived, so in that sense, they "earned" the right to draft high. In their case, the Spurs were fortunate that Robinson was available when they had the top pick. But that's no different than when Orlando got to draft Shaq and Milwaukee got to draft Lew Alcindor. That's part of the NBA's plan to help the competitive balance of the league.
In the Duncan draft, however, the Spurs were extremely lucky. They were 59-23 the previous year. Unless you think they would have tanked with Elliot and Robinson, there's no way they would have had the W/L record that put them in the third spot in the draft unless both of those guys get hurt. Even then, they had to get lucky to get Duncan. I submit that without Duncan as their lynchpin and his longevity, their run would have been much shorter. If you look at the talent in the 1997 draft, unless you think Tracy McGrady would have propelled them to the championship, there was no other elite talent in that draft - none. Given McGrady's subsequent health issues, if the Spurs had drafted third and selected him, I don't see any way they continue their "run" they way they have so far.
What I will credit them with is the ability to spot talent lower in the draft. Without the supporting talent of Parker and Ginobelli, would they have been as good as long? Probably not. In terms of their "run", they've been the beneficiaries of good talent selection, good coaching, but just as importantly, good luck.