There are logical reasons: capitalism for one. If you want to juice demand for Plaid or LR and feel that having Plaid + with 500 miles range and the new 4680 batteries (the true refresh) would delay or depress demand, it MIGHT make sense to "unannounce the Plaid + and stop sales. There are already more "inventory" Plaids showing up around the country.
If they didn't kill the Plaid + (with Elon's silly statement that no one needs more than 400 miles range), I would have waited for the Plaid + because the refresh I really wanted was a Model S with the new battery and all its advantages.
That being said, I agree with you and am almost certain we won't see a Plaid + in 2022 or 2023. They're not keeping up with demand using the old batteries as it is and I gotta think that the first few years of 4680 production are already fully committed to other vehicles. I'm hoping to see Model S cars with 4680s about the time I am ready to switch out my refreshed Model S (5+ years).
If it's sooner, I can wait a little and save time commiserating in line with like minded order holders. As much as I like this forum, I can't believe how much time I have had waiting for delivery to spend on it.