I don't know if you can use Bolasie and Mason in the same argument as Vassell. Bolasie came to us after he had had a stop start previously but when we sold him it was to a league side. Joe Mason, whilst coming through our academy did have his chance in the first team albeit briefly before he was again sold on but neither left Argyle for non-league only to be picked up and set on his pro career. In Isaac Vassell's case, he was never given a chance but once Luton picked him up from Truro he has gone from strength to strength and whilst I don't know how much they got for him both Truro and Luton have benefitted financially from one of what might have been a starlet.
Whether this reflects badly on us depends on whether it was a short termism brought on by administration and recovery that enforced the position on us and whether we learn from our mistakes and do right by players such as Battle, Fletcher and Sangster. Ask again once these players have or have not been given a proper chance.