Were they really forced to sell that particular player? Did they suspect he'd turn out this good? Seems more like a Cole Palmer situation, they sold him for decent money when they were maybe expecting him to turn out a decent player, but he turned out way way better than that so the deal looks terrible in hindsight.
Surely they did not expect him to turn out so good. Did they include a buy-back and 50% sell-on?
He does seem to be turning out better than they expected, perhaps similar to Cole Palmer. Though they didn't really get that much money for him considering the swap deal; maybe just over £15 mil (albeit pure PSR profit).
At the time of him being sold, most Newcastle fans really were not that fussed at all about him going. They thought he would struggle to get in to their team ahead of the likes of Bruno Guimaraes, Tonali and Joelinton. And he might have tbf, they have quite a strong central midfield already. They also have Miley coming through.
Some comments from the Newcastle forum at the time, you can find plenty more similar as well if you look:
"I've never seen anything in Anderson that convinces me he can go on to be a really top class player, so in the present climate I'm not too fussed to see him go. "
"Not too bothered about this as I don’t rate him much. Hopefully this means we will sign another quality midfielder. "
"Don't really see anything in Anderson to make me upset about him leaving - him and Gordon are best mates so that's interesting. Anyway best of luck Elliot."
"I'm actually less disappointed about this one than I am about Minteh. With Minteh or was the unknown potential for greatness. Love that Anderson is a local lad, but Miley has already shown more in a few games than Anderson ever did. He was (sadly) never going to get to the level we needed."
"I like Anderson, and think he could be good, but we're not going to miss him. "
"Sad to lose an academy lad but only ever been impressed with Anderson twice; Forest away (Isak brace game) when he came on at half time and Spurs at home this season. "
"I really can't help but wonder what Forest see in him and how they plan to use him. He's been a solid contributor for us when he's played, but it was more of a case of waiting for him to take the next step."
https://newcastle-online.org/topic/36600-elliot-anderson-now-playing-for-nottingham-forest/page/107/