>Both still own one home. Both are still consuming housing that's worth $25k/yr to them. Yet the government collects no tax revenue. Exempting the implicit value of rent is a subsidy favoring owner occupied housing.

Why stop at rent? Alice cooks at home? Tax implicit cost of dining out.

Alice goes shopping? Tax implicit delivery cost.

Alice conceives a child? Tax implicit IVF cost.

Alice gives birth? Tax implicit adoption cost.

Alice dies? Tax implicit execution cost.