And Harrison and Greenwald.
You also can't rule out that Hong Kong/China wanted to get rid of him, to keep from being embroiled in precisely the international brouhaha that happened.
Snowden applied for political asylum in 20 or so countries. If one of them had accepted - let's say Germany, Finland or India - then your hypothesis is no longer valid, no?
It seems very risky to do all that if his goal is to defect to Russia. Had one other nation granted asylum, it would have ruined his narrative.
Regarding "to defect", has he pledged allegiance or loyalty to Russia?
Otherwise, why isn't he simply an exile? Do you consider all of the Cubans who fled to the US also defectors from Cuba?