If it was just a matter of a bit of R&D why did we have spy satellites and planes like the SR-71 before such simple craft as a Predator drone?
You mean like the Lockheed D-21 Reconaissance Drone which attached to the top of the SR-71?
just shut the fuck up now
If you had read TFA you linked to you'd have noticed that the '...D-21B program was canceled, due to the poor success rate...'. These Vietnam period UAVs were just enough steps up the evolutionary ladder from a from a V-1 to make the potential of UAVs clear but they generated relatively little worth while reconnaissance on long range 'autonomous' missions. They did not have the AI capabilities that would make them 'autonomous' in the sense that drone designers and computer scientists put into that word. Modern UAVs owe much of their existence to the Ryan Firebee that was much more successful operationally than the D-21 since the Firebee system was very modular and flexible. Some of the Firebees were remote controlled but only on relatively short range missions (this being the AQM-34L the most successful Firebee variant by far), on long range missions they they followed pre-programmed routes and relied on simple sensors for major obstacle avoidance. Just one measure of how 'stupid' these things were in 'autonomous mode' is the story of a Ryan Firebee that was badly programmed for a recon mission to Kep Air Base and ended up flying along the entire airstrip at very low altitude. It returned with a sequence of pictures that showed every detail of the runway surface interrupted only by a single picture (or so legend has it) that featured a terrified NVAF MiG-17 pilot whose aircraft almost collided with the drone during landing. For those that are interested you can read more here I particularly recommend the picture of the MiG-21 whizzing past that Firebees TV remote camera.