A 10:7 ratio and Japanese security

Why would the equitable treaty be less likely to collapse in the 1930s?

A 10:7 ratio could make Japan feel secure while still constraining the United States and Britain, unlike a ratio that made Japan feel permanently weak.

The argument is that a 10:7 ratio would bind the larger British and American industrial bases more strongly than it binds Japan. Japanese leaders would still understand that they could not win an unrestricted building race, but the ratio would make the treaty feel protective rather than permanently humiliating. By contrast, 5:3 encourages continual demonstrations of strength because Japan starts from a position it regards as insecure. The intended effect is deterrence through sufficient security, rather than an illusion of equal war-winning power.