That's not a factoid. Thomas was a good player on a team that was super stacked. Just like the 2004 Pistons. You replace Thomas with Stockton on that 1989 team and they still win easily.
Again, look at that team. They were stacked. Dumars was a 6-time All-Star and a much better defender than Thomas with similar scoring numbers. He wasn't just given the FVMP. He outscored Thomas by 6 points a game in that series while averaging just one assist fewer. His TS% was better by 10 percentage points, too. The roles would reverse next year, but Dumars was a flat out stud. No, I'm not saying he was better that Thomas overall, but I
am saying that Thomas had Dumars. Dumars was 26 at the time.
He also had Aguirre. 3-time All-Star, including his ultimate and penultimate season in Dallas before being traded to Detroit. Easily put up 25+ in Dallas and had a great mid-range game, but could also score around the rim in all kinds of ways. He was 29 during those first Finals.
Laimbeer was top 10 in the league in all manner of advanced defensive statistics, and a 4-time All-Star. He could also get under an opponent's skin like no one else and probably the closest think basketball has seen to a hockey enforcer. 31 at the time.
Rodman was a DPOY in both 1990 and 1991 and whose defensive abilities even in his late 30s we all witness in those Jazz Finals and who was 28 when the Pistons first won it.
They had Vinny Johnson off the bench who was nicknamed Microwave for a reason and whose per-36 numbers put most starting guards to shame. He finished 2nd in Sixth Man of the Year voting once during that time.
Add to that a real supporting cast including Mahorn, Salley, and Edwards(remember, this is when most NBA team's firepower came up front, so you needed guys to handle that) and that's a team that would win the championship with most star guards replacing Thomas. They went 3-0, 4-0, 4-2, 4-0 in 1989.
Build a team like this around top guards in the NBA right now, and yes, they will win titles. Or any top guard from any other point in history. That's not to say Thomas was a scrub, but he was not the second best PG in NBA history, no matter what Jordan says. Bleacher Report had him at #10 not even a year ago, and that's probably generous too. The numbers(advanced or otherwise) probably put him closer to 15.
https://bleacherreport.com/articles/2852716-nba-all-time-player-rankings-top-10-point-guards