Yes, we can. (I know, I know... but it isn't intended)I imagine that the "triangle philosophy" referred to a programmers ability, not the amount
of resources available. So maybe in some sense it was true. If it was true in some sense,
then my refined question becomes:
"Can a modern programmer meet all three, unassisted"?
If your finished program meets all your performance, maintenance and usability requirements, you effectively did it. Thousands of programs shipped and will continue to be shipped that do just that. Necessarily this does not mean that in your code you didn't have compromised, here and there, something for something else. But your final variable is the program itself and how it stands to your objectives. It's unthinkable to believe that no program was ever developed that couldn't meet all the programming requirements. We would be in a lot of trouble to justify the world's dependency on computer technology.
I'm not sure why you keep reaching out for an "Yes" answer as you keep changing the terms of your question. Maybe you want this triangle thing to be true? I can understand why. It gives some assurance in our lives. It's the type of saying that answers bad programming practices with "it's just the way things are". But it's not how things are.