Despite being a memoir, the series is set in The Present Day *because* Technology Marches On. Literally.
Making changes to stories that accommodate people having cell phones is just a matter of the writers' room which includes Sundquist himself and they'd need anyway. Setting it in the early '90s would require functional, period-correct prosthetics whose cost would significantly add to the show's overall production cost. A present-day setting means they can just use the actor's real fake leg.
