Given that there are plenty of developed countries where credit scores don't exist (and plenty more where they do but only for businesses), I think alternatives are imaginable. I would know, I live in one such country.

If you want a mortgage here, the bank will:

Ask you about your current loans and potential past defaults
Ask you about your current and past income, marital status, employment status, etc.
Use those variables to pretty straightforwardly determine your loan capacity
I think do a background check in national databases for defaults/"bad payer" status
Contractually obligate you to receive your salary on the same account from which they will automatically pull the mortgage. I don't think this helps reduce actual defaults much, but it probably greatly reduces the financial and administrative overhead of late/missed payments. Also this ties you into the creditor bank which is good for business, IDK how standard that practice is abroad.

The US consumer economy is very highly dependent on short-term/credit debt, and that is absolutely crazy to me. Some Americans say they "need" a credit card to defer payment on some purchases, and as someone raised in culture where debit is king this sounds absolutely insane. Y'all have been propagandized, here it is perfectly normal to not have a single credit line open before shopping for a mortgage and if anything your banker will commend you for it.