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.