Luck was coming into the season coming off a scary shoulder injury that could've easily ended his career. He came in and had to learn a completely different offense under a new head coach. He was surrounded by a ton of new faces (Many of them were rookies, two in which started on the offensive line, and another being Mark Glowinski) while Anthony Castonzo missed the first 5-6 games of the season. Luck was throwing to guys like Chester Rogers and Ryan Grant. He had to adjust to new faces like Ebron and Mack as well. The defense was young and inexperienced which didn't help. Andrew Luck never had consistency and anywhere near the talent Rivers had during a majority of his career.
This 2020 Colts roster is the most talented roster they had since the 2006-2009 Colts. If Andrew Luck didn't retire and had the chance to play on this roster while Rivers stayed with the Chargers through this season, we wouldn't be having this conversation. Stats are so misleading. Look how many times guys dropped wide open passes on Luck that year. No one has done more with less than Andrew Luck and it's a shame people look past it because of the disastrous rosters he's been dealt with.