Maybe '21 is like '20. Maybe it starts like '20 but then demand slows down. Maybe it starts like '20 and increases in demand.
Who knows. Trying to predict new retail demand and used 2nd market demand is like trying to guess at a game like 'odds or evens'. You have a 50-50 chance of being right and if you get it right, then you think you know something special when it was just a correct guess.
Maybe demand will fall and there will be a flood of used bikes into the secondary market. If so, then OK then. I dont understand why people make fun of those who eventually sell their recreational equipment in a relatively short time after having purchased it. Perhaps they tried cycling and found that it sucks. Perhaps they liked cycling, but it didnt fit into their schedule/routine. Perhaps they liked cycling, but like something else even more. Perhaps they liked cycling and bought an even more expensive bike and are now selling the cheaper one.
Even if someone buys a $2000 bike, happily uses it for a season, and sells it for $1100- why is that seen as a bad thing? So many posters on this forum(and elsewhere) regard that person as a fool for having bought the mid-priced bike and laugh at how they will be able to buy nice bikes for cheap in a year or two when 'everything' hits the used market.
Its really an odd mentality.