1. It's a deployment of some infrastructure change the government got the big tech companies to sign onto.

2. It's a "shot across the bow" from some external party to demonstrate their control over major infrastructure.

2.a. Also could have been a mix of 1 and 2. The government orchestrated the outages in order to add fuel to the hysteria over Chinese "spy chips". However, given the story every time seems to be "Someone goofed a configuration", this theory doesn't seem to have much life left in it.