“Whether you are shipping 100 boxes of cellulose insulation or 100 boxes of computer chips, transportation from place A to place B costs about the same.”
Chips, solar panels and batteries got cheap because a few giant factories make them. Insulation and 2x4s can’t travel far without the freight eating the margin, so they come from thousands of small plants. Small plants don’t invest in process improvement. That is a big reason construction productivity has gone nowhere since 1960 while everything else got cheaper.