High speed recon vehicles alt timeline
1959 Navaho interim unmanned recon vehicle. Mach 3.25
1960 Power is shot down. A-12 manned vehicle to complete the Navaho
1962 first flight of the A-12 Top speed Mach 3.6
1963 Fish resurrected and now launched from a Valkyrie. Mach 4.2
Dyna Soar program go ahead
1968 Fish /Valkyrie combo enter service. A-12 and Navaho withdrawn.
1971 Dynasoar enter service for recon.
Of course, the corona KH-4 exists, but drawbacks of spy satellites are well known