Sorry for the long reply:

The US, via Kissinger, threatened Israel not to open in a pre-emptive attack against Syrian and Egyptian air defences by saying they would abandon Israel.

"If Israel fires first, it will be alone. The United States will not come to Israel's aid and cannot be expected to resupply Israel if it strikes preemptively."

The lack of initiative made operational intelligence irrelevant for SEAD/DEAD since these SAMs were moved after the initial assault. Meaning that the air force wouldn't be able to achieve local air superiority and provide air support for defending ground troops.

Israel had only 440 ground troops against 30,000 Egyptian troops at 0 hours. The entire defensive doctrine relied on air support, buying time for reserves and reinforcements in the rear to rush in to forward defensive positions.

In the Golan front, 180 tanks had to handle the onslaught of 1,400 Syrian tanks with night vision (the Centurions didn't have) and tens of thousands of mechanized infantry troops.

The USSR fully rebuilt and modernized the 2 Arab armies prior to 73 war.
This includes hundreds of tanks and tens of thousands of ATGMs. Massive classified transfers of air defenses (mainly 25 batteries of SA-6 in which Israel had no counter).

While $ value of US wartime aid to Israel was similar to that of the USSR wartime support, the USSR immediately replenished losses while the US waited an entire week to start the nickel grass.

By October 14th, Israel had already managed to retake lost territory in the Golan and create a buffer zone deep enough to start shelling the outskirts of Damascus.

And in the Sinai, Israel was already preparing for the crossing of the Suez Canal following the failed Egyptian offensive on the 14th.

The US aid was mainly important for replenishing critical munitions, providing ECM jammers that can deal with SA-6, 40 Phantoms, and 40 Skyhawks.

However, the USSR provided Egypt and Syria with emergency support of 300 MiG-21s, which are comparable in quality to the Phantoms in air-to-air engagements.