The author briefly mentions DaltonLens. Use one of these colorblind plug-ins? Is it find colorblind testers? Is it add more labels to sprites and graphics, and words to UI? Is it strictly avoid Red-Green color pairs?
Add a different shape, size, outline, or if it really has to be color only make the difference be not just hue but saturation and luminance as well.
But the worst offenders are always maps with color gradients ranging from red to green.
Obviously that won't work for all kinds of colour blindness either but I can't figure out a straightforward way of representing this particular thing without colour ... it's literally about a graph colouring problem. Patterns/textures maybe? But then the nodes would have to be larger than I'd like so that there's enough surface area in each node to recognize the pattern, and then it would become very crowded.
For creating contrast in other ways: saturation and brightness are unaffected by colorblindness and you can create contrast with them.
Barring that as a red-green colorblind person, yes red-green contrast is the worst, but way more common are colors that are only different by their red or green strength (especially red). The two most common by far being pink becomes white and purple becomes blue.
Your green-yellow-blue suggestion is actually making the same mistake as red-purple-blue just using green as the fade instead of red. Having said that in my experience red-green colorblindness is actually RED-green colorblindness. So, I would much prefer a green-yellow-blue interface to a red-purple-blue one. As I am much more sensitive to green than red.
So you use Lab* as HCL with your designers or, my HCT's T, and tell them that all T / L* must be at least 50 away from eachother for text, and 40 away from eachother for controls.
The solution is astoundingly simple but requires some commitment
It does not have to be perfect like a green checkmark and a red X. You can use your own, but consistent shapes (filled circle vs a ring) and add a on hover label. We can adapt, as long as it's even possible.
The author touches upon it; expanding on it would take another full-length article.