I fall in to that camp. I don't look down on 'theoretical CS' stuff, but it's rarely ever even had to be a consideration in projects I've worked on, which has included ecommerce systems selling billions of dollars of stuff (large qtys, small price per item), real time reporting of financial data, and numerous other projects requiring a degree of scale or speed or both (php, vb, java and other stuff over the years).

Not everyone works on facebook, nor is everyone writing real-time device drivers, nor is everyone writing something that will explode up in users tomorrow, devastating the business if not every customer is served in less than 50ms.

I may be one of those in the 'get it done' camp, but I've also learned over the past several years to opt for using well-known libraries when possible, to take advantage of the expertise and skills that I don't have (yet). 15 years ago, I was firmly in the 'write it from scratch and focus on performance, tightness, elegance, etc' camp, but not so much today. Part of that is because we simply didn't have the wealth of free software libraries we do today, so you had to write more stuff from scratch, but that's not as much of an excuse today.

I've yet to have to write a binary search after 17 years in professional software development, and my projects have not suffered because of it. I had probably a good 10 years of hobbyist time before that, so I probably have simply picked up 'good' patterns to common problems without necessarily knowing the specific CS theory or names behind them in some cases.

All that said, my answer to performance issues in my apps is generally not 'throw more hardware at it' - I will profile to look for bottlenecks, isolate specific areas and rewrite sections of code to make them more performant, which sometimes means changing how data is organized/stored, or modifying queries, or something else.

Lastly, while I think I understand the type of person/attitude you're talking about "full of self-important people like this", I don't think I see myself in that particular camp (but of course, no one ever does, right?). There's a degree of pragmatism that needs to happen in 'real world' software dev (isn't agile all about "you ain't gonna need it"?). I've also had to 'clean up' after enough other developers over the past 17 years - including myself on a number of occasions - that my perspective may be sufficiently different from the type of people that work in company X for 10 years and rise to the rank of 'sr dev' only ever having worked in one or two places. Or maybe I'm just a self-important ass who's justifying himself too much in public?

EDIT: One other thing that has popped in to my head - I've worked on more than couple projects where other people on the team (before me or concurrently) insisted on certain things being done "right", simply because that was the "right" way. Two things were apparent - they typically didn't know any other way at all (lack of experience) and they had no understanding of what the real use of the application was - never talked to end users or other depts/units, and were creating far more work for everyone else by not implementing things differently (in their minds, 'compromising on correctness'). Couple different scenarios in the past few years spring to mind.