When you think of the ages we bought Walker, Rose, Davies, Eriksen, Dier, Dele etc. We knew at that time that whilst it's nice to unearth a Kane, Mason or Winks from Edmonton or Enfield, you just simply have to keep targeting that 17-22 age range from elsewhere and then nurture the hell out of them.
My feeling is that whilst we do some, we just don't do enough if it. We are too risk averse in this area and don't always buy the lottery ticket anymore. Everything you say above is clearly correct but also applies to every other club. Now as the 10th biggest club in Europe, who should be favourites to land them? Are we even in the race? Do we do a good enough job of selling the vision of THFC?
My other fear is that because of Lamela, Sanchez, Ndombele etc it might even make the club even more risk averse. That's why I say let's be a Dortmund for a while and send the message to every youngster that Spurs give these talented kids a chance. We create space for them. That's all.