This is more or less true, but an interesting thing to think about is that the number of people (with technical backgrounds) making 7 figures in financial firms is smaller than the number of people making 7 figures in technology firms. This is probably obvious to you if you work in finance, but I think most outsiders don't realize that.
If you include people with sales backgrounds like investment bankers then the numbers might shift in favor of finance.
If you want specific examples from tech then the Waymo article from a while back is helpful, but that doesn't mean that you need to work at Waymo or Google to get there, although a large portion of those roles are at Google-tier companies.
Your average agency will not be hiring pure developers and paying them 7 figures, although they might to someone who is generating revenue and bringing in enough business to justify it.
> My question, specifically, is, what fraction of engineers in tech make 7 figures
I doubt that OP meant that they literally have data showing that it's 1-5%. That's a wide enough range that it's meaningless. I suspect the meaning was more "way above average, but reasonably possible".
However, I bet most principal engineers and up who have been here 3+ years are hitting that lately with how good our stock is doing and that amazon pays higher ups mostly in RSU's.
It seems plausible to me at least that there are more ordinary engineers that have won the stock options lottery across all of tech than the total that are earning equivalent amounts in finance.
Losing all visibility/ability to publish/being a first class contributor and not second class dev..
But, I agree, finding alpha through alternative means at internet scale has been around for at least a decade, but things are getting more interesting now.