Really depends on the server specs. Tab amount relies entirely in memory & CPU availability, not in the infra that runs behind the scenes
But yeah, in one server we can fit hundreds of browsers, or even thousands if we use bigger servers. And each one of them with dozens of tabs, no issue
Something doesn't add up between the pricing and the core pinning for me (or maybe I misunderstood):
Say you're using a m8i.large (2 vCPUs, $0.043/hr on spot pricing). Is the article saying you dedicate a whole physical core to one browser or am I totally misunderstanding here? If so, are you taking a loss on every browser hour?
But yeah, in one server we can fit hundreds of browsers, or even thousands if we use bigger servers. And each one of them with dozens of tabs, no issue