Did Galileo really disprove Ptolemy, or could Ptolemy's model be adjusted and still defended?

Ptolemy left room for adjustments, but they would have to be major ones; you had to move Mercury and Venus outside the sun's orbit, which takes a lot of doing, because he did not know where Mercury and Venus went. What Galileo actually disproved was where Ptolemy had placed Mercury and Venus, and he could do that easily because of the phases of Venus: you cannot see the phases of Venus in Ptolemy's model, but we do see them, so any model claiming to be correct has to show the phases of Venus, and Galileo's did. But the real question was whether his heliocentric model was the only one that could show the phases of Venus, and the answer is no. What Tycho Brahe brought us with his geo-heliocentric model was the game-saver; it was the best that could be done at the time, and it also shows the phases of Venus. So Galileo disproved Ptolemy's placement of the planets, but he did not thereby prove heliocentrism.