I had flights from Toronto into Gatwick, home from Dublin booked for April 2020, rebooked them for this April for just a tiny bit more (think honestly like $15 more, each). The new dates are "nicer" - later in the month, nicer times on busier days, and the trip itself is longer. We booked later than we did for the original flights (I think the original flights were booked at the beginning of January during a sale, I didn't bother waiting for a sale this time and just booked). But what's really notable is that my mother-in-law also booked with West Jet, from Victoria, and only paid a little bit more than us. Of course there are layovers, but usually Victoria would be a ridiculously higher price.
My mom booked her original flight on Air Canada. Beyond the issues of getting any credit from them whatsoever (they claim they never cancelled her flights, and that she just didn't show up . . . she has the emails to prove otherwise, but then was too blinded by grief during the extremely short refund period to pursue a refund until later, and they have casually postponed sending her the credit vouchers for several months now), the AC flights were wayyyyyy more expensive than the original. Her original flights were YVR-LHR and then Dublin-YVR. AC flights almost doubled in price, seemingly no matter the day. Combined with the issue of actually getting credit, she found it more worth it to book with WestJet AND "gifted" herself a couple of days in Paris and more days in England. So despite adding (at least) 5 days, not worrying about the dates, flying from a smaller airport (Kelowna), and doing more expensive days and longer flights . . . she ended up paying significantly less than she had before.
I feel like WestJet has responded to the pandemic by going "Well let's get any passengers who are trying to get a trip!" and AC is more focused on potentially fewer passengers but higher ticket prices. . . . I ran into the same dichotomy trying to book flights to BC later in the summer - while I did end up choosing AC (and Swoop for the way back), WJ was cheaper for most dates.