From 1917: War, Peace, and Revolution, by David Stevenson (OUP Oxford, 2017), Kindle pp. 229-230, 232-233:
Caporetto transformed rather than terminated Italy’s war. The tensest period was late October, when sbandati [“disbanded” soldiers] and civilian refugees swarmed over the Tagliamento bridges. By the 31st the main Italian forces were over the river, but four days later the Central Powers crossed it and Cadorna ordered a retreat to the Piave. By 10 November the Italians held the new position and assaults immediately began against it, at the same time as Conrad, belatedly and with much weaker forces, attacked in the Trentino. A further month of fighting followed until the Central Powers, having failed to make significant gains in either sector, wound the campaign down.
The campaign failed, therefore, to knock Italy out, but it was even more successful than the attackers had anticipated. The Italians no longer menaced Trieste, and would launch no further major offensive until October 1918. They withdrew by up to 150 kilometres, and an area normally inhabited by 1.15 million people fell under occupation. The Italians lost 294,000 prisoners (thousands of whom perished), 12,000 battle dead, and 30,000 wounded, as well as half their artillery. Given that over 350,000 became ‘disbanded’, only half the field army remained operational. In comparison, German and Austrian killed, wounded, and missing totalled some 70,000, of whom about 15,000 were German. Even so, Hindenburg felt ‘a sense of dissatisfaction’: the triumph was incomplete.
The new team at the top in Rome would make a difference only gradually, and even the French and British divisions, though doubtless a morale booster, came too late to decide the battle of the Piave. The major part in halting the invasion came from Italian soldiers, whom opponents such as Rommel now found were fighting harder. Orlando told Diaz it was ‘absolutely vital for the national interest’ to hold the new front, which was 170 kilometres shorter than the old one, from which change the Italians benefited. In addition, the collapse had largely been confined to the Second Army, whereas the Third and Fourth held the Piave line, and the sbandati were reintegrated into new units. The government also called up the 1899 conscript cohort, so that before the year ended the army was almost back to pre-Caporetto numbers, while by the spring it would largely recoup its equipment losses. To be sure, British and French deliveries assisted, especially British gas masks, but Italian industry accomplished most of the task. Psychological recovery was harder, as over the winter food supplies remained critical and in several regions the civilian mood was fragile. The army sat out the cold in improvised positions and the military authorities, who continued monitoring troop morale, were nervous. The first two wartime prime ministers, Salandra and Boselli, were among many politicians who now doubted whether it had been right to enter the conflict. None the less, with the Germans gone the Austrians were again on their own, and from now on conditions on their home front and among their troops deteriorated while those of the Italians improved. 1918 would see less fighting than in 1917, much of the action being confined to the unsuccessful Austrian attack on the Piave line in June and the final Italian advance at the battle of Vittorio Veneto. This was a transformed front, and one that became the Austro-Hungarian army’s major commitment. Yet although Caporetto in the short term had spectacularly fulfilled the Central Powers’ objectives, in a curious way it weakened them in the longer, as Tenth and Eleventh Isonzo had weakened the Italians. Italy’s political unity and military morale improved in the aftermath and it received more Allied aid. But in the longer term still, among the consequences were the strengthening of ultra-nationalism and the PSI’s move towards extremism, paving the way for the rise of Fascism.