Why equal treaty rights do not require equal naval spending

What is the value of equitable allowances if France and Italy cannot afford to keep up economically?

The allocations are maximum rights, not spending requirements; France and Italy can build less without forcing Britain and America down to the same budget.

The question argues that an equitable treaty is pointless if France and Italy cannot afford to keep pace with Britain and the United States. A legal maximum is different from a construction obligation. France and Italy historically did not use all the tonnage available to them, and the proposed treaty would not require them to do so. Britain and America would also reject a ceiling deliberately held low enough to prevent their fleets from exceeding the budgets of second-tier powers.