This is assuming two shipments is "worse" from Walmart's perspective.
Fulfilling 2 of an item from a store might trigger a resupply, which takes truck space, which pushes other, higher-margins out of stock or into danger levels, etc.
Which isn't to say that Walmart's system isn't "dumb", but is to say that it's a very complex system, operating in realtime, and what look like dumb outcomes may in fact be optimized (according to whatever internal goals their logistics system has).
Fulfilling 2 of an item from a store might trigger a resupply, which takes truck space, which pushes other, higher-margins out of stock or into danger levels, etc.
Which isn't to say that Walmart's system isn't "dumb", but is to say that it's a very complex system, operating in realtime, and what look like dumb outcomes may in fact be optimized (according to whatever internal goals their logistics system has).