This came up in the RKCC meeting where they were announced -- June 2021. There was no RKCC meeting in 2020 as there was no Blade Show, thanks to the fallout from COVID.

Anyway, back to the question: The design was underway/completed by 2013. There were assorted delays in bringing them to market, including (but not limited to) retirement of two senior knifemakers and a COVID pandemic.

(Edited to add) My understanding is that 17s are a little more difficult to produce, largely due to the stainless hilt. This is why dealers have a limit on how many 17s they can order each month. I suspect it took some time to make 200 of them during a period where they're trying to catch up on their schedule.