There will always, for example, be a conflict between availability and confidentiality. Ultimate confidentiality might require that the data be stored in an inaccessible bunker with no outside access. Ultimate availability might involve hosting sensitive data on a publicly accessible server with no access controls.
In the real world we must always balance these needs carefully, and triage available resources to achieve an "ideal" outcome. This means that security will never, and can never, be a solved problem.
As an example, diplomacy, open source, shared interests, universal basic income, and education can reduce the desire for attacking. How do these factor into the CIA triad?
I would answer that the triad IS useful in this scenario and further that if we used an alternative model (The 7-C's maybe?) we would still find inherently contradictory requirements for almost every security scenario. In fact, we would just MORE more of those trade-offs, further proving that security can never be "perfect."
For example, I can think of several fundamentals the triad doesn't cover directly. Privacy and non-repudiation spring to mind as concepts that don't neatly fit into the CIA triad, but they are the antithesis of each other!
Perfect privacy would require that nobody (including data-owners) can identify the user, and perfect non-repudiation would require that no access be granted without 100% proof of the current user. Again, you are forced to choose and this means that some aspect will always be less than perfect.
No, this is the same sort of defeatism that prevents us from making progress on security. We could engineer usable systems where actual security is a priority, and not just security theater. We don't because nobody in a position to change anything actually gives a shit.
Security is a priority. But it's not the only priority.
It would be difficult engineering even if it was the only priority, but given that there's little point to security for a system you never deploy, it's not likely to ever completely monopolize focus, either for users or implementers.
Ultimately though, they know that no matter how many times their failure to invest in security results in their customer's data being compromised or destroyed they'll keep making money.
Their customers are corporations who have insurance to cover their expenses when Microsoft's failure to make security a priority inevitably leads to a breech and those corporations are able to avoid all accountability for their decision to use Microsoft products no matter who else gets hurt as a result.
Dealing with yet another security issue caused by Microsoft is just another cost of doing business. It's still cheaper and/or easier for the corporations to keep MS and deal with the endless vulnerability/patch cycle than it is to move to something else and pay people who know what they're doing to manage those new systems so nothing changes.