Sure.
But think about your own experience.
How many Pentagon "think tanks" and "operational analysis" wargames would place a MLRS group (theirs OR ours!) under direct fire from an enemy mobile group of infantry, Humvees/jeeps/APC's?
It happened!
Sure, it wasn't "supposed" to happen. Those things (OURS and THEIRS!) are supposed to be protected behind miles of "front-line" defenses .....
But it happened.
No weapons system is perfect in every environment. Towed artillery has difficulty in rougher terrain. And does the fact that MLRS aren't any good in a direct fire shootout mean that we shouldn't have any MLRS? Our M198's weren't doing much against those tanks. Maybe SP mortars would have been able to scoot a bit better. As it was, we were stuck.
Or maybe think about the artillery raids we did into Kuwait before the ground war kicked off. We did those with towed howitzers, which obviously caused a problem. Guys got killed in when one truck/guy combo tipped. If they were in SP mortars, they would have been far more effective for shoot/scoot missions.
The SP's are a nice element to add to the fire support package. They are light enough to get in theater easily, and far more mobile once they get their with towed. Better to have a mix, like they're talking about now, then having all M198's.