Note that this most recent outage (NOTAMs) had nothing to do with ERAM.
ERAM is employed the the 23 air route traffic control centers [1] throughout the nation as their primary operating system. If there were a system-wide outage of ERAM, the consequences would be magnitudes more consequential than any NOTAM outage. Basically every flight in the air and not close to a terminal facility would lose radar contact and controllers would be working blind, causing widespread chaos and likely many safety incidents. Non-radar air traffic control is a thing, but generally controllers do not have adequate training or currency to do it safely, and definitely not at anywhere near normal capacity.