I think it's essential to become an XWP ("X Who Programs") even in mainstream software shops.
Well, it wasn't essential to Linus Torvalds, or Doug Cutting, or Joel Sposky.
If you enjoy data science and machine learning, do data science and machine learning. There's a lot of cool stuff going on in that field. But don't use it as an excuse to look down on people in different fields. There's too much of that going on already (and yes, developers do it sometimes too.)
I can't speak for Doug Cutting, but is my understanding that both Torvalds and Spolsky are XWP for values of X=Really good at managing projects and programmers, and in the case of Spolsky also pretty good at the whole running a business thing.
Certainly in Spolsky's case I don't think he writes much if any code at Fog Creek or Stack Exchange. Torvalds probably still codes a fair amount, but certainly when it comes to Linux most of his value comes from the architecture and management side of things rather than the lines of code he writes.
Everyone is an "X who Ys" for some value of X and Y. The question is what's your main job? If the answer is writing, reviewing, designing, or philosophizing about code, then your main job is software engineer. All three of the folks I mentioned fall in that category.
I had a friend in college who was extremely proud of his double major in biology and computer science. He went on to get a PhD in bioinformatics. He was fond of telling me that being "just a software engineer" would never be as exciting as the work he was doing in his specialized field (not going to go into details, but it was related to pharmaceuticals.)
A few years later, the pharmaceutical industry is in a slump and he can't find a job in his specialized field. So he's working on web design for a while, hacking PHP etc. I'm doing the same thing I've always been doing, working on distributed systems, and it's been very rewarding. (Before you ask, I did try to find a job for him, but he didn't want to move to the west coast.)
The moral of the story is to do what you really like and are good at, and don't worry about people telling you that you absolutely MUST shift your focus to X to succeed (where X = being a manager, being a quant, learning biology, etc).
But don't use it as an excuse to look down on people in different fields.
Oh, I don't look down on "pure" developers (as opposed to XWP) at all. I just think that it's hard to establish a reliable stream of good work on engineering cred alone, because the people who make decisions in most businesses can't tell the real deal from the charlatans in software engineering. The X is the "hook" that gets you enough clout to ensure you get interesting work and continue to get better as an engineer.
Well, it wasn't essential to Linus Torvalds, or Doug Cutting, or Joel Sposky.
If you enjoy data science and machine learning, do data science and machine learning. There's a lot of cool stuff going on in that field. But don't use it as an excuse to look down on people in different fields. There's too much of that going on already (and yes, developers do it sometimes too.)