I'm starting to see some large lithium battery backup generators.
They benefit from being dead quiet, no fuel cost, no fuel jell/varnish, no smell, and no maintenance. Good for off grid camping, etc.
Some new company called Mango has a 3kw and can be found on discount for about $3100 (~$1/watt). It'll drive a 30amp load.
I saw a 2kw on Amazon for $1600 ($0.73/watt).
For comparison, a Honda 2.2kw is about $1200 ($.55/watt).
Hopefully costs come down over time as competition increases etc.