In my post on hand washing David Mannheim did a quick estimate suggesting that the time costs of handwashing more often would roughly break even, based only on the expected work time saved from not getting colds. That's before factoring in effects of your cleanliness on the health of other people, the physical unpleasantness of being sick, or any diseases other than common colds. So my guess is that the cost-benefit analysis of having better hand hygiene is strongly positive even on a normal year; even more so when you take into account the small chance of stemming the next big epidemic.
For two of the other main things that generally get recommended for day-to-day hygiene, not touching your face and coughing/sneezing into your elbow, the cost is mostly in building the habit, so if the habit is already built as a result of this pandemic then the cost seems trivial.
My hope is that we'll build a lot of tools/infrastructure that doesn't require ongoing costs to maintain (i.e. whenever you have a button that hundreds of people are pressing, or door handles they're opening, etc, find some alternate solution that doesn't require them to use their hands)
I think people will initially be more careful with ongoing habits (i.e. handwashing and face-touching) in the wake of coronavirus, but that this will fade within a few years.
Should humans be less disgusting? All in favor, raise your tentacle...
There is so much low-hanging fruit. Doctors don't wash their hands consistently. Parents send sick kids to kindergartens and schools. They are told repeatedly; and they ignore it. Cost/benefit analysis? If I send my sick child to kindergarten, it's your cost and my benefit; that's all I need to know.
If you're worried about a pandemic always being looming, the changes you want to push are more systemic (e.g. those covered in this 80k podcast episode) than what's discussed here, but decent point.
I've heard people say that this should be the trigger to be more careful about disease after the pandemic is over: e.g. people with mild colds shouldn't leave the home without a mask, all big events should have hand sanitiser. One example is this opinion piece by Matt Ridley (content warning: politics). What's the evidence on the cost/benefit analysis of marginal hygiene in rich countries when a pandemic isn't looming?