Inability to easily load data from last year's return to this year's return

I've used TurboTax for Mac since it was MacInTax, now a long time ago.  In recent years, I've found it impossible to upload a prior year's return into a new year's return.  Doing this used to be stupid-simple, not any more and it's annoying.
Volvogirl showed me how to do it on a non-Mac but that's no help.
Why is it so opaque?