Yeah, the problem is that the Internet is dominated by the voices of the PC generation, who somehow never learned that there actually was a long history of computing before the PC and MS-DOS.
CP/M and other precursor OSes are really only of interest to historians and nostalgic geeks, but DOS actually has some real relevance to many people and projects even today, thanks to FreeDOS and the fact that we're still running x86-compatible machines... which is sort of astounding, actually.
Sure, there was a long history of computing before the PC and MS-DOS, but it was constrained to very few people for the most part - specialists, hobbyists, professionals, academics, and so on. But it was really the PC, running MS-DOS for the most part, when the vast majority of people were introduced to computers for the first time. So, it's not all that surprising that DOS is seen - rightly, I think - as the OS most used at the beginning of the personal computer revolution.
Even so, I don't think that many people mistake that for the beginning of computing in general. If nothing else, they saw computers on TV, with walls of reel-to-reel tapes and flashing lights.
The interview was about DOS, so I didn't talk about the other stuff before DOS (and after).
Our first "computer" was a mainframe acoustic coupler dial-up terminal my mom brought home for a week, so she could do some work at home. I wasn't very excited about it at the time; it was all business software and I was like eight years old.
I seem to remember we had another computer in the house at one point. Not a TRS-80 but something along those lines.
In 1982, my family bought an Apple clone (Franklin ACE 1000) and that was where my brother and I taught ourselves to write programs in AppleBASIC. I was fascinated by computer interfaces that we saw on TV and in the movies, so I wrote programs that emulated those, including the thermonuclear war simulator from the Wargames(1983) movie.
Some time after that, we bought an IBM (I think the XT). And that's what got me started with MS-DOS.
We used MS-DOS at home (upgrading to the '286 and '386 and '486) until I went to college with the family's old '386. During my university days, I had an account on the VAX and the Unix systems. I discovered Linux, and switched to that on my own computer (dual-boot with MS-DOS). I mostly avoided Windows at home, although I did run Windows 3.11 and Windows 95 for a short time - mostly for games. At work, I ran Apollo AEGIS/DomainOS, HP-UX, AIX, SunOS/Solaris, and Linux (RedHat 3.0.3 and later). Work also put me on a Windows NT4 desktop, which I ran for a while until they let me run Linux at work full-time. In the office, I've run either Windows (whatever was current) or Linux. At home, I just run Linux (I'm running Fedora Linux now) and use DOSemu or QEMU to run FreeDOS.