You don't need vacuum tubes. That's such a horrible audio myth. They glow in the dark and look nice. Aside from that, they produce more distortion, more noise, use more power, are more fragile, and have shorter lifetimes than solid state electronics. They do not sound better, given $X spent on whatever, presuming some reasonable amount of tech is returned per dollar.
OTOH, if you just want to make vacuum tubes because.... you want to make vacuum tunes... have at it :)
You are mostly correct. Vacuum tubes are less efficient, produce more distortion (generally speaking), are less efficient and more fragile, and have shorter life expectancy that solid state components. However, a well designed vacuum tube amplifier will sound better to most listeners. The reason for this is the type of distortion produced. Our ears/brain "hear" a big difference between 2nd and 3rd order harmonic distortion, and it is the former that those glowing glass devices are noted for.
Speaking for myself, and having built several amplifiers based on some of the most respected designs available to the DIY builder, I was absolutely astounded at how much better my first single ended triode (tube) amp sounded than anything I had ever heard. Mind you, I am no clueless audiophile snob. I don't hear a difference between 18 ga lamp cord speaker wires and overpriced, "oxygen-free", "audiophile-grade" speaker wires. I do hear a difference between solid state and an SET, and it is profound. Now, I will qualify that claim by noting that most SET amps are low-powered affairs, that demand rather special (highly efficient) speakers. They are not at their best with loud/complex program material, but when fed a well-recorded acapella vocal group, jazz or classical ensemble, or even some Steely Dan, the result is nothing less than breathtaking. The same can be said for tube-based headphone amps. Not every pair of headphones is a good match for this type of amp.
But then most listeners think that the .mp3 material going through their Beats headpones is "hi-fi", so anyone who can make a buck off that crowd by "sticking tubes in the circuit" is just as guilty of taking money from suckers as is the manufacturer selling a $900 cable that "...increases warmth and air..." In other words, the worth of a given technology is in how it's implemented and not nearly so much in the nature of the components.