Even in the last couple of years we haven't done badly with our lower league signings, like Burrows, Cooper and One.
We've signed a number of established players with background from the top two divisions the past few years and that's expensive, especially in terms of wages. They've not all been old like Ings and Mee, but most have been around for a few years and I think most of us have known about them when they signed, like Campbell, Shackleton, O'Hare, Chong, Tanganga, Rothwell, Riedewald, McCallum, McGuinness.
In Matos and Cannon we did try to go for expensive potential, but it seems our assessment of them was way off.
So we've largely gone for established, pretty expensive players, not potential. These types of players may do a decent job (or not) at this level, but they are a) unlikely to suddenly develop into PL players and b) unlikely to give us much of a profit.
Our abroad recruitment has been poor and I have no idea what kind of foreign scouting structure we have. It seems a waste of time to suggest/discuss targets abroad at the moment.
So, yes, agree, we should probably look more for talent in the lower leagues!