There was something special about the 60s in the US. Your comment implies you might not appreciate how absurd the SR-71 was. The F-35 is our latest fighter jet. It has a top speed of 1200 mph, the SR-71 had a top speed of 2200 mph. The F-35 is capable of operating at around 50,000 ft, the SR-71 was capable of operating at 85,000 ft. The F-35 has a self fueled range of about 1350 miles, the SR-71 had a self fueled range of 2,900 miles.

Look up aviation records and you'll find the SR-71. It even still holds the #1 spot for the fastest airflight (by a plane) ever. Basically, the SR-71 is old, but old doesn't mean antiquated. The 60s was the era that we went from knowing basically nothing about space, to putting a man on the Moon in 7 years (Kennedy gave his 'to the Moon' speech in 1962, first landing 1969), while we currently flail about trying to recreate it with a program lasting into the decades already. The SR-71 was another product of this era.

The US also had two superlative poles of engineering excellence, Kelly Johnson's Skunkworks and Hyman Rickover's nuclear submarines. They've been since replaced by bureaucrats without an ounce of talent.

No one questions the technical achievements of the SR-71. It doesn't make any sense to try to resurrect them though.