In the past, the typical household only remained in this relatively ‘risky phase’ for a few years, mainly because its nominal income rose quickly (partly due to inflation), and secondly because its debt was reduced by principal repayment. In a low inflation environment, nominal incomes rise more slowly and so households remain in the ‘risky phase’ for longer.
If they have fully factored this into their financial decisionmaking, it should not present a major problem, but if they are still operating on the assumption that 4 inflation will quickly reduce debt burdens, they would be taking more risk than they perceive.