Fulham's stadium must be one of the most valuable just by it's location. How much would that land be worth?
Transfermarkt values are just numbers. They are set by people just like us and often not updated for a long time. With assets like that a reasonable idea would be to estimate the value and divide by at least two. Consider someone like Lukaku, who in Transfermarkt is considered our most valuable player at 28 million: he could be injured, or he could simply sit out his contract. What value would he then be? Leeds thought back around the turn of the century that even they overspend they at least have the assets on the pitch. But they found out it's not enough if you set them a price, someone needs to be willing to pay it. And that's why it's foolish to think a buyer will look at Transfermarkt and consider that sum.
And even if the club could sell players with a reasonably high price, so what? They would need to be replaced or the squad would get worse, which would lead to worse finishing positions which would mean less money. It's not like the players are surplus that can be sold. The real value lies in how the club has been doing and potential to improve (both on and off it).