I notice that chromium.org does not require SNI.

SNI was created so that multiple SSL-enabled websites could share the same IP address. (Perhaps because IP addresses are an undue expense for some website owners, unlike, say, chromium.org.)

Assuming the the single IP address is not "anycasted" (another undue expense), does SNI imply that multiple websites1 are in some way sharing a common computer?

Could that be relevant with respect to "site isolation" in any way? Why or why not? (For example, does the server side, perhaps with multiple "tenants" sharing the same hardware, pose a risk to the client concerned about undesirable memory access?)

1 Presumably those websites are handling sensitive information hence the need for SSL.