This question brings back memories! My mother did not change out her sewing machines very often, but whenever she did, I recall my dad altering the cut-out as needed.
Last year the motor went out on my 91 year old mother's Kenmore. She definitely did not want a new sewing machine for two reasons: she did want to have to learn a "new fangled" machine, and Dad isn't with us anymore to make the cabinet alteration. She didn't have to worry -- her Kenmore ran good as new once the repairman worked on the motor brushes.