>>676
The generalised usage here ("be <period> <gerund phrase>")
is in my experience uncommon, old-sounding and/or dialectal.
It seems to be used only to emphasise that the time period was
long, and not to make objective statements about the time
taken to do something. For example: "she was years getting over
the breakup". (Meaning that she took many years to get over it.)

It's definitely in use by some speakers, but not many.
I hesitate to agree that it's standard usage.
Feel free to share more contemporary examples that you come across.