This is important information from Jamie G Price on the differences between Wi-Fi Retries, and TCP Retransmissions.
There is an additional 'penalty' imposed by 802.11 protocol on Wi-Fi Retries - each time it happens to a frame, there will be additional delay time added to the next transmission to try to help the transmitting device find better chance of NOT getting a collision and retry - each time the backoff timer DOUBLES.
So high Wi-Fi Retries indicate issues with RF congestion.
In some instances, ALL the possible Tx devices are stuck on the most onerous backoff timer setting because of this. (Think Times Square on New Years Eve with hundreds of thousands of Wi-Fi devices all within earshot of each other)