Agree. The Spurs built their defense around Murray, with White taking the bench defensive duties. It was a risk but it might have worked. Murray's injury not only derailed this year's defense, the Spurs have to go into next season not knowing if they have to spend the summer completely retooling their defensive pieces or if Murray alone is capable of carrying the Spurs into a better than league average finish in that category.
I know some Spurs fans scoff at the idea of a point guard being able to be a defensive foundation but it makes sense in this run-and-gun era. Look at the L

kers, their defense has fallen off a cliff since Lonzo got hurt (IIRC, they're something like 6th defensively with Lonzo and 29th without him). And Murray >>>> Lonzo defensively.