All the proposed airplanes look really cool, and as someone who taught in the T-38 for 15 years, I'm certain it will exceed the Talon in sortie duration, ease of Transition (especially landing), turn radius, acceleration, and an air conditioner that will not suck while blowing.
That being said: previous contenders (T-50 and M-346) were advertised in the $30 million each-range 8-10 years ago.
Cost to purchase is pretty high...but operating costs for fuel will probably exceed the Talon. While turbofans will be better than the J85s, the new engines are MUCH bigger. So, while SPC may be 4-5 times better, TOTAL burn will be higher.
Maintenance is a huge manpower cost on the T-38. Will the new kids be better? Almost certainly not, at least, initially, until mx learns the new jet.
Some T-6 FAIPs that were former students of mine "flew" the Lockheed T-50 Sim. They said it was awesome...and also WAY too much airplane for Phase III training. The complexity(and capability) of the avionics would be overwhelming.
I would tend to agree...great IFF airplane, but no manufacturer wants to build just 50-70 airplanes.
I still think a cheaper airplane, more like an L-159, would be plenty to teach jet flying, aerobatics, formation, and tactical. Then, use a jet such as these proposals for the lead-in to Fighter Fundamentals.
The Air Force is going to stack the deck for Congress, though. They will say the T-1A is worn out, and they need to go back to a one-track system (which means they'll need 350 new trainers instead of 50).