Why did amplifier manufacturers abandon tubes

The question is incoherent because the alternative to 'tube' is not 'digital', but 'transistor' (or 'solid state').

The alternative to 'digital' is 'analog', and these are different ways to encode sound, and have nothing to do with reproducing sound - which is where tube/transistor comes in.

(It is perfectly possible to reproduce music that is recorded on a digital medium over a tube amplifier, or to play music recorded on an analog medium over a solid state amplifier - which for about 30 years was the only way to do it).

But accepting that the question is actually about the tube/transistor dichotomy, most answers seem to get it right: Some people prefer vacuum tube amplifiers because solid state amplifiers perform better. So the vacuum tube amplifiers are basically equivalent to an old woman plastering her face with powder so that you can't see the wrinkles.