4nm -> 3nm no longer means size goes down as a result directly ratiometricly. You have to look at what TSMC is claiming for their improvements. They're claiming

4nm -> 3nm no longer means size goes down as a result directly ratiometricly. You have to look at what TSMC is claiming for their improvements. They're claiming 5nm -> 3nm is a 70% density improvement (I can't find any 4nm -> 3nm claims)... so 4->3 must be much less. Also, most folks seem to have gone directly from 5nm to 3nm, and skipped 4nm altogether.