You can still get them. I just found a “professionally reconditioned” Selectric 111 on Ebay.
Found it with mah trusty macbook.
I typed my master’s thesis on one in 1984.
It’s gone, but I salvaged three `daisy wheel’ models in our office. Got two to work, have cartridges with both text and correct-tape in reserve.
Still easier to type an envelope address on a typewriter, JMHO.
I pounded out newscast copy 1976-80 on a Selectric. All caps. Never used the correcting feature.