The formation of Kievan Rus was far more complex than that.
In the 700s, before any Varangian activity in the region, there existed already three realms in East Slavic territories, mentioned by Muslim writers Al-Gaihani and Ibn Haukal - those were Kuyavia (with the capital in Kiev), Slavinia (with the capital in Novgorod), and Artania (probably with the capital in Ryazan). Later, but it isn't certain when exactly (from the 800s to the late 900s) also Haqaniyya by the Azov Sea (which controlled Tmutarakan) formed.
Rurik and his Varangians may be credited with uniting those realms into one, rather than starting the whole thing.
This is also the role that Nestor of Kiev in his Primary Chronicle ascribed to Rurik - and to his successor Oleg - that of unification.
Another controversy is what or who was/were - originally - the Rus? Some claim that it was a demonym for some tribe or group. But for example Omeljan Pritsak suggested, that it was probably a "trading company" originally founded in southern France (but with a network of influences throughout most of Europe), which employed Varangians to protect their trade routes, just like later the Byzantine Empire employed them as guard units.
If Pritsak is right, then the formation of Kievan Rus could be - to some extent - similar to that of British India. The East India Company exploited political landscape of India and through a combination of alliances with some of local caciques and wars against others, extended their control.
But some scholars are sceptical when others suggest the existence of "trading companies" during the - so called - Dark Ages.