Bdtyktl

The General Question, short version:

Should one try to justify why one wants to drop out of a programme in favour of a job one is applying to?

Why I'm asking / the context of my particular situation:

I'm in fairly early stages of my PhD programme but already quite convinced academia is not for me. I haven't really accomplished much in my time here - my current PhD programme (and a one-year Masters preceding it) was a little pivot from my prior position in the industry which I've now realised was a mistake - I want back into industry.

I realise that "I thought that doing research in blorp was a good idea but it wasn't" is not a great narrative to have in my job applications, and would just add unnecessary clutter to cover letters. I'm not likely to be able to give it a positive spin, as it's early stages of research so I haven't gained any relevant knowledge other than becoming aware I don't want to do this. I'm a little tempted to just leave it out, and let the school mentioned in CV with recent starting dates do the talking. Is that generally a good idea?

You do not have to address it unless it is brought up, but if you do, be honest, direct, and brief.

I've made a clear and final decision to persue a career with your company. I do not believe that continuing my graduate work would be a productive use of my time.

or

I've always had a great love of this industry, what my stint in graduate studies did was make me realize that.

or something similar.

What you want to emphasize is not that you're leaving school, but chasing after your first love, the industry you want to go back to. Put it in as strong a term as that (but use your own words).

TO SUM UP:

You are not running away from graduate studies, you are running TOWARD your passion, which is the industry you left.

To do a PhD is a significant commitment: you pass the viva or you don't, there is no second place. If you are doing it in the US, it's even more challenging because of the increased duration.
It's perfectly normal to reconsider such a massive life commitment. There is nothing wrong with this.
But you need to think hard about what motivations led you to apply for a PhD, what made you interested in the experience and what you wanted to get out of it.
Not accomplishing much in the first year or so is perfectly normal: that's when you do your literature review and get familiar with your field. Things will keep accelerating until you are hurriedly writing your thesis because 4-5-6 years have passed like nothing.
Think about it a bit more, and if you still want to leave academia make sure that you can provide a good narrative. Somebody will ask "why didn't you move to another PhD project or programme?", and they might wonder whether you wanted to do a PhD, or just do research on that specific project. There is a huge difference, and you need to communicate it accordingly.