Powell is expected to join Manchester United for £4 million.
"We go from feast to famine as we have always done in the past," stressed Hassall to thisisstaffordshire.co.uk. "When our youngsters come through it pulls back the deficits we have made previously.
"We made over £2m losses over the last two seasons and that is not sustainable in the long term as none of us (the directors) are multi-millionaires or blessed with oil wells.
"But we'll always have a market for the likes of Nick Powell and the Max Claytons of this world, although not for the players who stay with us a bit longer. That is why we need to be in category two for Academies so we can persuade youngsters to stay with us."