I've been in/around QA for about 20 years now, after 5 years as an app dev and doing a career semi-shift during the 2001 downturn. For the last ten years or so, I alternated between SWE and SDET titles depending on the job, and before that between QA and QA Automation Engineer. That history is where I'm coming from here.

In short, there's been a lot of title inflation in QA, in part to avoid the "black box tester" stigma for both the employees and the organizations alike.

One of those inflations has been calling what were QA Automation Engineers--generally people writing scripts--SDETs. I saw it start to rev up in the late 2000s, and saw it accelerate (maybe not coincidentally) in the early 2010s, shortly after a GTAC talk where they claimed SDET makes 30% more on the average than QA. I suspect a lot of people asked for title changes, or a lot of managers realized they'd also look 30% better managing SDETs than QA and advocated for them.

Thing is that SDET as originally conceived was/is supposed to be a Software Engineer who specializes in testing, with the same qualifications and training as any mainline SWE. The normal domain of SDET would not be scripts, per the other response, it'd be tools, infrastructure and harnesses, maybe seeding test frameworks for incremental development during test creation, usually along with some level of QA thought leadership.

The primary difference there would be the ability to scope, implement, and maintain longer-term software engineering projects. A QA Automation Engineer might be as skilled a coder, but test scripts tend to be short bursts of isolated code and don't require as much architectural or lifecycle experience.

But SDETs are also useful in cases where you want to blur SWE and test, since most SDETs have heavy experience in both and can talk shop and build rapport with both sides. That comes in very handy when pairing with a mainline SWE, hence mentioning it as a near-requirement for that process.

No offense to you and your journey, but I'd have never stepped back from an SDET role to a QA Automation Engineer. It really is objectively worth less in the market, for one thing, and there really is a stigma there with QA in the title. It shouldn't be that way, but it is, and inflation has been the natural response.

Re: advocating for quality from the beginning,

Testing is by nature quality control. You can do it early, you can do it late, but at the end of the day it's a screening process.

That's different than Quality Assurance, which is monitoring and influencing the process and decisions when they're made to promote and advocate for quality when determining the good/fast/cheap project management compromises.

That includes arguing for testability as a primary requirement, arguing against overly complex requirements likely to produce emergent bugs you can't easily catch with QC, pointing out gotchas (hey, everyone is on vacation in December, expect crap code rushed checkins in November), basically anything you can do to reduce risk.

So in that role you're not a tester, per se, but a Subject Matter Expert in quality, hopefully influencing a whole team towards testable products, intelligent context-driven processes and good use of test pyramid, use of static analysis and other code quality techniques (think SonarQube), etc.

All this is over and above just testing, because you simply can't test quality into a project, you can only delay it until it's good enough. That type of gatekeeping is an adversarial tension fraught with both process and organization risk, and it should be avoided.

When you're an obstacle, people will have the natural tendency to work around you and resent you when they can't, which makes it an unsustainable dynamic to rely on as your 80% case. Ideally, most testing should just confirm what you already know: you have a solid process that caught all major bugs before you ever did a final pass.

Even if your org is going to just go full QC instead of QA (which is pretty typical, unfortunately) being able to absorb the full architecture and use cases around what you'll be testing is vital for coming up with an efficient and sustainable test strategy.

If you've been in QA any length of time, you know that these qualities--efficient and sustainable--aren't exactly associated with that corner of the process. A lot of that is because QA/test is often relegated to reporting on how a bug repros and how severe the issue is. You could be doing so much more, but that requires cooperation from the people around you.

When I was doing my time as a QA Engineer before swinging back to SDET, I did this by leveraging my SWE experience to talk shop with devs in low level terms until they trusted me. But it's a hard road to climb, particularly if you didn't have a flipflop like I did.

I hope that answered your questions. It does reflect a degree of personal bias, of course, but it's pretty well-informed by a long time in this corner of the industry.