If they try calling Plus "J" or charging J prices for "J" (or C or D) while they still offer the 3 X 3 seats they are likely to see people wave at them through the windows of the AC flight they booked and paid for J on. (Or AV or CM or AA etc.)
Which means they will have a lot of PE seats on offer for the next two + years.
I like WS say to SJO but part of that like is that the Plus seats are cheaper than paying for the real J seats and service on Copa. Ditto to YVR. I am not paying WS AC's J prices for what is now Plus vs. flying on AC in J seats.