Qwiss Maybe not 20m, but genuinely thought he was worth close to at least 10m. Certainly not be making a loss on what we bought him for a decade ago.
A quick look also finds that many random no mark CBs age 25-30 moved for around 5-10m pounds in the top 5 leagues, not including those higher profile players that costs 10-20m that I don't even think it's better than Holding.
The idea that we can't shift our players out for reasonable fees because there are no demands for them, but many other clubs could is just flawed. It's mainly due to the reputation we got ourselves into for the past 5 years, overpay for players we want, write off players we don't want.