tube gear vs solid state...cable effectiveness

Yes, cables remain very important with both SS and Tubes. With tubes though, alot of the annoyances involved with HiFi seem to disappear or at least diminish. Things like only sounding good at 3:00 in the morning, or when the fridge is off. Or sounding bad for days after vacuuming (I'm not kidding)or when computers are running. Tubes can sound so right and likable that these problems vanish or become unimportant. I suspect cables may be less of a "Life or death" decision for good sound with Tubes, but you will still need to tune the system with the proper sympathetic cable choices till you get it just right. Possibly not the same choices that worked with your SS system, but I wouldn't dump your cables till you at least try them with a new setup.

"... cables make more of a difference on solid state and are not as effective on tube gear."

Ridiculous in my experience.

sub $3k for cable? cable may make a difference on both designs again depending on design, but it has nothing to do with price. the price of cable is only for brand and not for performance. one $5000 cable may sound like cwap vs. cheap radioshack. for performance you should match it to the parameters of the component particularly output impedance characteristics. i'm wired with pro-grade cables and wires that match good my components with total price <$300 for all of them.

Perhaps, wire seems less important to tube equipment owners than solid state owners because the first step taken to tailor the sound of tube gear to one's particular taste and system interactions is to change out tubes.
With solid state gear, there is MUCH less ability to alter the sound so one is often limited to wire substitution. Hence, in that sense wire choice is more critical with solid state gear because there is little other means of fine tuning the sound.

I can hear more cables differences on tube gear than SS. My 300B amp reveals sonic differences with just about any PC, interconnect, or speaker cables.