Why don’t tube amps sound like tubes anymore?

Your resistor type,and coupling capacitors hav3 a large say in its voicing , as well as the tube type and brand. Power cords And cables used also Can have a large effect in the voicing .many people forget even 10 years ago many things have changed.

IF anybody needs a Quad 303 to convince themselves, let me know....

@mijostyn +1

Actually, it is more like modern SS amps are sounding more like Tube amps.

I sold my tube amp because the Pass XA30.8 gave me everything my tube amp did plus what it lacked in low end grip, dynamic range, and a silent black background. I think Class A SS done right is very satisfying to tube lovers, especially when combined with a quality tube preamp.

In most circumstances at audio shows, I can tell when I walk into the room, sight unseen, if it is using tubes or solid state. There is still a difference in presentation though not nearly as much as, say, 20 years ago.

The old SS vs Tube battle arises yet ,,once again,,, I thought that war was finished and over for all time, ,,guess not,,battle lines have been drawn. 
I am a  front line warrior for tubes. 
For me, ss technology is ,,dinosaurish.
Now I will say  quality tube gear is expensive, and NOS tubes are essential only fior pre tubes,,,power tubes new is just as good/ better than NOS (which are wayyy over priced)
A Tele pre tube is worth every penny. These  are not over priced. 
Seems everytime ~~The Final Nail in the old ss coffin~~ just doesn't seem to hold,,out come the ss gear  rising from the grave.
Translation/bottom line : ss gear is over priced and over rated. 
Note: this is not to say there is NOT some crappy tube gear out there. 
2nd note: hard to find any ss gear to come  close(midrange fq;'s in reference, not bass/nor highs) to a  quality tube  unit. 
3rd note,,I've heard a tube amp intergrated retailed for $2100 back then, now like $3500+,,  make music sound live in your room. 
can you supply  the name of a  ss lab that can match that experience?