The Army doesn’t retire old Abrams tanks. They reset them to the latest configuration. This has been going on since the M1A1 was produced from scratch.
Did you read the OP?
“The first M-1 entered service with the Army in 1980. The original M-1 packed a 105-millimeter gun. The Army bought 3,300 of them. In 1984 the Army added thicker armor to a batch of new M-1s and called these 900 tanks M-1IPs. The U.S. military no longer uses these early M-1s.”
Not any more - they are scrapping the remaining M1A1s that they can’t sell to foreign powers.