The Italian navy had several advantages over the British Mediterranean Fleet. At the start of the Mediterranean War, they had a numerical advantage, especially in lighter ships like destroyers and cruisers. In June 1940, the RN had 4 battleships, 9 cruisers and 25 destroyers, against 6 battleships, 21 cruisers and 52 destroyers (and ~60 large torpedo boats/small destroyers). The British did have an aircraft carrier, but the Italians had airbases surrounding the contested waters. While British reinforcements and Italian losses would close this gap somewhat by Taranto, the advantage was still on the Italian side. The Italians had a qualitative advantage - two of their battleships were of the modern Littorio class, and their older ships had been extensively modified. The British had no modern battleships, and only a few of them had been modernised. Finally, the Italians had an advantageous strategic position. The British had bases at the western and eastern ends of the Mediterranean, each holding significant forces, that could if brought together represented a significant threat to the Italian fleet. Individually, they were unlikely to defeat the Italian force. The Italian position in the central Mediterranean offered such an opportunity for such a defeat in detail. However, there were serious issues with the Italian fleet. It was lacking in the two main things needed for a successful naval campaign; fuel and confidence. The Italians did not have enough oil to maintain their fleet at sea for long periods, as they would need to gain naval superiority over the Mediterranean. They also didn't have the confidence needed to threaten the RN. When battleships did enter battle, they were kept out of reach of any possible threat, limiting their effectiveness. Where the Italians had superior forces, such as at the Battle of Calabria, they didn't press this numerical advantage.

Taranto forced the Italian navy's heavy units to use bases in northern Italy. This slightly increased the pressure on Italy's fuel situation. It also gave the British more breathing room - now Italian ships had to steam further to threaten British operations, giving the British more warning and more chance to make air and submarine attacks on the Italian fleet. It also further decreased Italian confidence - with the losses at Taranto, they had (though temporarily) lost their numerical advantage in battleships. Battleships became something to hoard and protect at all costs, even when it affected the chances of success in a battle. The best examples of this are the two battles of Sirte. At both, strong Italian forces, including battleships, threatened weaker British cruiser and destroyer forces protecting convoys travelling to Malta. If the Italians had pressed their advantage, the British would have been helpless to resist. However, because the Italians didn't want to risk even a miniscule chance of losing a ship, they spent both battles at long range, and withdrew as soon as possible.

The Italians probably wouldn't have been able to escort more supplies to North Africa if the raid on Taranto hadn't happened. The main threat to the convoys was from air and submarine strikes based from Malta (and for submarines, from Alexandria). The Italian defences against these were less affected by Taranto - the destroyers, torpedo boats and escorts remained at their bases in southern Italy. While British surface raids against convoys did occur, they would not be prevented by additional covering forces - they tended to rely on destroyer ambushes at night using radar, which the Italians had very little protection against. Additionally, in the one case where the British engaged a convoy with a strong covering force - the Duisburg convoy in November 1941, which had two heavy cruisers as a covering force - the covering force failed to effectively coordinate with the convoy, and never engaged the British force. Had more supplies successfully reached North Africa, it would have been difficult for the supplies to be shipped forwards - the rail and road links forward to the front line were generally insufficient for the amount of supplies that were shipped, let alone any more hypothetical arrivals.