Then ... in voiceover, Allan continues his pejorative lament while walking up the hill to his neighborhood launderette.
... and Now, Near Coit Tower, this is Grant Avenue on Telegraph Hill looking south towards Filbert Street. He is just passing 1653 Grant, approaching the corner at Greenwich (map). The awning above the doorway is still there and the window has since added security bars.
Then ... He muses on while doing his laundry.
Back then the G & G self-service laundry was at 501 Greenwich Street on the corner with Grant; listed below in the 1972 city directory. The exterior wasn't shown in the movie but it's reasonable to assume, since the camera crew and actor were already there (as seen above), that this is where the launderette interior scene was filmed.
... and Now, 501 Greenwich today is a rentable shared workspace office for professionals, a concept that didn't exist 40+ years ago. Workstations have replaced washers and dryers.
... and Now, this exterior view of 501 Greenwich shows the door with the awning down the hill on the left that Allan passed by in the image at top of this post.