Anyone who bought/leased just before the pandemic when supplies were normal will have significant equity now, 3-5 years later, which could be used during trade in time, but I sense and I could be wrong that this sharp appreciation in prices will now moderate i.e. this was a one time major gain. However unless new vehicle supplies improve the differential between new and used prices will remain tight. I doubt though that we are going back to the pre pandemic paradigm of mostly being able to buy off the shelf with either the dealer you are shopping at or a nearby dealer having the spec/trim that you are looking for being readily available. As long as this new normal of order and wait for a few weeks/months for your vehicle to arrive remains, the differential between new and used prices will remain tight.
There is also the price point issue. A friend was shopping recently for a Highlander hybrid....a 1 year wait list, but he got a Lexus RX 350h in about 6 weeks, it's a platform mate but $20-25K more expensive.