My theory is that we are trying to be a Poundshop version of the Man City academy while in the Championship. Not sure who thought it was a good idea. City can sell their seniors who don't make the step into their 1st team squad to lower level Premier and top end Championship clubs for multiple millions each season which probably means they're making a healthy process out of their academy.
We can give away ours who don't make the grade to league 2 or lower. The only way we make money out of our academy is by getting players into the 1st team squad and the occasional sell-on clause. To be fair, we have made good money from Tav and Spence but Spence was bought in rather than developed in house. In the last seven years, we have only had one academy player who was developed through the academy get sold for more than £1m. That seems poor.
That said, I suspect that 1 player making the grade each season is probably about as much as you can realistically hope for.
This season, Coburn accidentally made the grade and was doing ok until his injury. We currently have Hemming and Brynn out on successful loans but unless we sell Dieng, there's no route for them here. Probably means they get sold for a 6 figure fee each to league one or Scottish Premiership plus sell-on clauses. Bilongo has done ok at Ebbsfleet, and you could imagine a league 2 club buying him for a nominal fee and a sell-on clause.
Last season, Coburn and Brynn both had good loans.
Season before, Hackney had an important loan even if it didn't go well and stepped up on the back of it.
Before that, Jones had a decent loan and got into the 1st team squad.