Didn’t really think of it that way, but if you think it’s possible, then go right ahead.
Had some discussions about it on another site, and the best POD I’ve come across does indeed start with no Mongols, with the subsequent setup casting Galicia-Volhynia as the successor to Kievan Rus (sacked 80 years before the Mongols came along, even IOTL). Despite that, the lack of Mongol invasions allows Rus as whole to survive, with Galicia-Volhynia linking up trade networks with its neighbors. In time, it’s overtaken by Kiev, now the fledgling leader of ”Rus”, which styles itself as a vaguely “HRE meets the Hanseatic League!”-style confederation of trade cities controlling the main rivers and canals between them.
(Muscovite rule and Boyar authoritarianism is butterflied, too, so there’s that.)
Decent-sounding POD, I think, though as far as my additions go: It’d be a the mother of all ironies if ATL equivalents of Classical Liberalism and free-market economics emerged in Rus instead of Great Britain. Bonus points if Rus somehow became an “Eastern America”, both in the sense of wild frontier-land on the periphery where the locals have a spirit of mercantile ventures and rugged individualism and in the sense of an emerging superpower that sweeps aside its Old World rivals. Probably a stretch to have Rus survive that long, but still a fun thought all the same.
