When we are comparing tech maturity here, it is important to remember that 1970s saw a change of technologies in satellite imaging - photographic satellites, which captured images on photographic film (i.e analog imaging), were replaced by electro-optical satellites, which captured data in digital form. Photographic technology was mature in 1973, which is to mean that it had its developmental kinks mostly worked out; but due to its analog nature, it had certain limitations that were not due to tech immaturity, but inherent to the tech.
In 1973, the satellites that were available to USA intelligence would be KH-8 Gambit 3 and KH-9 Hexagon models. They were more or less equal in their photographic capabilities, the main difference relevant to our subject being that Hexagon's camera was designed to take stereographic images, which made interpreting them somewhat easier, but Gambit 3's single camera could potentially achieve better resolution. Based on info available, both satellites could take photos with resolution of 1-2 feet, and under ideal conditions - Gambit 3 could achieve resolution up to 4-10 inches, depending on current distance to surface. Even the worst case scenario allowed for the recognition of military vehicles and to some degree identification of the type (i.e. it's enough to tell a tank apart from a truck or an APC, but you likely won't be able to tell one Soviet Cold War-era tank from another).
A more important difference was in the number of reentry vehicles. Why are reentry vehicles important? Because before digital imaging took over, the film had to be physically returned to Earth to retrieve images (some experiments in scanning film onboard the satellite and transmitting the data by radio were made in the 1960s, but apparently results were unsatisfactory; regardless, this wouldn't solve the problem of film being a finite resource). This is the most important tech limitation I was talking about. Gambit 3 Block III, which would be the model available in 1973 carried two return vehicles; Hexagon satellites carried four. At no point in 1973 would the USA have more than two such satellites (that I know of) up simultaneously, so what you got was six series of photographs, after which you would need to launch a new satellite to get more. That meant the decision to take that satellite photo was not a simple decision to make - and the cost of a bad analysis that wasted that shot was, quite literally, astronomical.
Digital imaging, which became available in 1976 with the launch of the first KH-11 KENNEN satellite, eliminated this problem; now you only had to worry about how long the satellite could stay in orbit and/or powered. But these were still in development during Yom-Kippur War.
Another important point to cover would be that even after you got your images, you still had to interpret them - manually. That means that someone had to sit and look through hundreds (or possibly thousands, if you wanted to compare newer images to older ones) of photos, and then make sense of what they were seeing. This process was quite time-consuming, and, as the anecdote you quoted shows, the results often came down to subjective judgement.
To sum it up: USA photographic spy satellite technology was quite mature in 1973, but was more suited to long-term observation and strategic analysis than gathering of quickly changing information such as day-to-day troops movement due to limitations inherent to base technology.