I agree with your overall point, but Smith was probably the best bench player in the Final Four. She would have gotten minutes/points even without Lauren's injury. But she's the exception.
She may have been, she is certainly a dynamic player, but ... in her last four games of the year she had:
9 minutes, 1-4 for 2 pts. 1 rb, 1 asst, 1 st, 3 fouls
8 min, 3-4 for 6 pts, 3 rbs, 1 blk, 1 foul
8 min, 1-2 for 2 pts, 2 rbs, 1 blk, 1 foul
and then in the final with Cox playing 29 instead of 40 minutes:
17 min, 7-9 for 14 pts, 6 rbs, 1 blk and 5 fouls.
So S16, E8, and Semi she averaged 8 minutes, 3 pts, 2 rbs, 1 blk, 2 fouls and the first two games were blow-outs.
I think Miss State and Stanford come to mind as teams who have fairly deep benches and get some scoring off the bench although not necessarily in the most important games....
I agree that Stanford and MsSt play their benches more, but scoring is an other issue in second weekend games:
MsSt bench played 29 min and scored 7pts in a 23 pt win and 16 minutes and 8pts in the loss
Standford 67 min and 25 points (but 3 starters combined for only 8 pts, and all five accounted for only 30) in their win, and 53 min and 10 points in their loss.
For Stanford two starters combined for a total of eight points during the weekend so they either get bench points or die.
The issue I am making is that generally teams have a hard time identifying 5 complete players to start and both score and play defense. There are very few that can, and generally the drop off when they then go to their bench is pretty dramatic. For teams that do not have five really good starters, then what comes off the bench may actually be just as good as the player they are replacing. They may play a few really good games as may any bench player, but you cannot count on it.
Uconn like Baylor this year, sometimes has a really good generally young player on the bench who can produce good games. Smith was such a player, but with her racking up 10 fouls in 42 minutes in her last 4 games she can't exactly be counted on yet. Sort of like ONO.