The worst thing is load balancers with a 10 or 20 second timeout, because there's almost nothing you can do other than use Opera Mini or something.
At that point, why would you use Google Maps at all? Osmand will do the same thing, and requires no connection.
If you assume that mapping services on a low-to-no bandwidth connection are important to them, they'll hear about it through word of mouth. Anything that solves a real problem will spread that way.
Contrapositively, we can conclude that mapping isn't much of a problem for these people.