What gives you that idea?
Well, just look at Milos and what it did for him, getting a coach like Blanco.
Niemayer with a lifetime high ranking of 134 is not going to be able to push Vasek to be more ambitious and disciplined. If Vasek gets inside 100, many in Tennis Canada will have a "happy with that" attitude. This is what keeps Canadian players stuck in mediocrity for so long.
Blanco's career high was 40; he recorded victories over Sampras, Corretja, Ferrero... he knows what it takes to play at a certain level. Blanco and Niemeyer are the same age and both played about 10 years, but look at the difference in Tour-level wins (or even matches played).
At times, Vasek looks lost out there to me -- like he doesn't have a plan. He needs to find a playing style and game plan that works for him and learn how to stick to it & call on it when under pressure, rather than just reacting to what's happening. That's the difference between a Challenger-level player and a Tour-level player.