I don't think this true. The successful resistance to Russia is due to the current strength of Ukraine's military. They have been improving rapidly in response to 2014. Georgia is nowhere near as strong or easy for us to supply.
Georgia is pretty sparsely populated apart from the capital - half of the population lives in Tbilisi. Relatively easy to create air defense for such a country.
Georgians took one of these routes early on and tried to collapse the tunnels but were driven back by russian airforce before they could do it.
Given enough material support it was perfectly possible to stop Russia there. But I wasn't even talking about that - even just introducing serious sanctions in 2008 would probably prevent the further escalations by Russia. Instead we persuaded Putin that we are divided and won't react. So he tried in Ukraine and Syria. And Ukraine again.
And when we finally reacted seriously he's suddenly surprised and accuses us of "trapping him" :)