I agree, our quest for tone is largely pointless.
I would modify that a bit. IMHO good tone is fairly important to me as a player. If my sound on stage sucks it has a pretty significant impact on my playing. So yes it makes sense to buy a rig that gives you the sound you want on stage.
I totally agree with this sentiment as far as how you sound out in the audience. In my experience the biggest problem tends to be bad acoustics. Bad acoustics means the audio tech does not really have control over the sound, especially the low end.
The second biggest problem relates to disagreements over how the mix should sound. Ideally everyone in a band should have a pretty similar idea of what the mix should sound like. But in many instances, each person in a band has a significantly different sound concept. If the members of the band can't agree to a common sound concept, it's impossible for the audio tech to make everyone happy. Also the audio tech will most likely have his/her own ideas, which vary somewhat from the band members.
Regardless, the idea that an audio tech can or should take your sound and spread it around the room without changing is both impossible and misguided. IMHO your sound should be processed separately for location and intended usage. What works for you on stage may sound awful in the FOH mix. I do agree that the audio tech should honor your tone concept for the most part. But he/she also needs enough artistic freedom to make adjustments, so your tone sits in the mix.
Ideally the best you can do is hire a skilled audio tech who consistently mixes in a way you find acceptable. Then over time you work together to develop a common vision of how the band should sound, and also develop trust so it's possible to negotiate reasonable compromise in difficult acoustic environments.
If you are working with an unfamiliar tech, the sentiment expressed above is extremely relevant, and I would suggest accepting the reality that you will have little if any control over what the audience hears. That does not mean you can't benefit from bringing your own awesome rig so you get what you want on stage, but sometimes that is not practical. If you want to have any impact on house sound, the band should contact the tech before gig day to work things out.