Neil was never keen on touring and wanted to spend more time with his young daughter. He also had chronic tendonitis and admitted that it was a struggle to keep playing at the level that he wanted to. Alex's psoriatic arthritis was another contributing factor.I thought Rush retired due to Neil Peart getting ill (and eventually passed). Of course Alex's arthritis is devastating too.
Maybe now Geddy Lee can learn to sing (I'm kidding and do enjoy some Rush).
Neil was diagnosed with a brain tumor about a year after their final tour and retirement, and he passed away in January, 2020.