I was also disappointed with the article in that regard.
OPL was not a MIDI device. It was a synthesizer. Whether Windows, or any given game, stored and played music via MIDI is irrelevant. You can use anything as a tone generator or synth, and you can use any back-end storage and sequencing method you want. The two don't have anything to do with each other, and I would expect a subject matter expert to be writing the article, and the head of a company whose career exists around PC audio to know and understand the difference.
I expect the author just isn't that technically astute, and Mr. Creative Labs has probably forgotten most of what he knows, having focused more on financial reports and business strategy since probably the SB16 days. The other tidbit that makes me believe this is the comment about sampling rate vs. word size. You don't need higher frequency sampling because 8-bit audio can't resolve that kind of detail above the noise? Not at all true, but OK.
The end bit is just marketing BS, as the company struggles to stay relevant despite the industry having moved well on since then. I don't know what 3D Surround Crystalizer Ultra-X is supposed to do, but I'll take faithful reproduction of a digital signal over any of that garbage, please. I also don't really buy the "modern motherboards are just so noisy" bit. I've had some motherboard audio that could be quieter, but most of it is pretty good. My Macbook's headphone out is quite adequate, and I can't recall ever hearing it think in the background. My modern PC passes its audio through the video card's HDMI out, so the quality and SNR of sound has nothing to do with the computer, and everything to do with the thing it's plugged into.
They did a good job of extending their life as long as possible. Wavetable was a huge thing for me, and I got tons of mileage out of the AWE and Live! as a hobbyist desktop musician. EAX made it compelling to try the Audigy series. After that, the game's sound engine has all the environmental processing baked in, leaving very little for the sound card to do but convert digital samples to analog audio. I'm sure the SB line is fine at doing that, but ... it's hardly mandatory anymore.