At this point it's too late, and before that they didn't really need advice or some fancy technology, they needed to dedicate enough resources/people/effort to simply do proper maintenance of their IT infrastructure. It's also plausible they simply couldn't afford the required resources, but that's not something fixable by CISA or other federal agencies.
It’s really easy to cut back on your IT infrastructure until stuff like this happens, and suddenly everyone is up in arms about why something isn’t working.
But it makes great budget headlines, “I slashed the IT budget in half!”
Hardly anyone is interested in defensive security because if you do it well your job looks unnecessary. This goes both at the national security level and the individual organisation.
When an extremely high profile attack like this happens, CISA ends up taking over the organization and revamping the entire organization's IT team. This happened to Atlanta back in 2018-19. It doesn't mitigate the current incident, but helps prevent the next one.
I don’t think there’s much to be done retroactively. I’m sure there’s an option for proactive help (trainings, advice) but it is a big country, some attacks will slip through.