You say
'caveat of shopping around for vouchers', but in reality it takes me a couple of minutes to buy and redeem a code. I normally buy a few of them at a time too. I'd say that was much less of a caveat than selling a game which will take up a good chunk of time, plus depending on where you sell it there may be selling fees, PayPal fees, postage fees etc.
Obviously if a specific game doesn't happen to be on sale the console isn't going to be sitting in a box for months, there isn't a shortage of games
. Digital edition might not suit you but it doesn't mean that it doesn't offer superior value to other people. Personally I buy 1 or 2 full priced multiplayer games per year that I know I will put hundreds of hours into, which at the moment happen to be slightly cheaper digitally anyway. I don't need to play the latest singleplayer games at release, they can wait a year or two until they are at rock bottom prices, at which point it probably costs me less than the price it costs people to sell it.