You need to drive and fine tune a Ferrari because it feeds your family. The OP just drive a nice little car, because it is fun to drive and he enjoys it. He could extract another +5% of torque by fine tuning, but he does not care, this is not where his joy is and where he wants to spend his time.
To be completely fair to the person you're responding to, they're talking about pages that take 20 seconds to load. On a regular website that hopes to get visitors from search engines, say, that is indeed insane and the fix is not to squeeze out 5% by fine tuning, the fix is to re-architect the thing
I don't mind people asking why it is this slow (whether I can't or why I don't re-architect it) or suggest fixes, but as the sibling comment to yours (from u/monooso) put it well, it would be nice if one does not assume that I'm an incompetent fool. The person also doesn't seem to read what I explained before suggesting more of the same in another reply. Thanks for adding your comment as well, I appreciate the sentiment. Even if I'm not sure if it applies in this case, it definitely applies to other things I do (I may have too many hobby projects running on that server.. ^^)
Well said! At work, I deal with these kinds of issues, and they get messy. I've spent hours this week discussing and debating table indexes and caching parameters for a system that's been running for fifteen years but we think we can improve. There's a diminishing return to putting tons of your time into every little thing, especially when a project is not your livelihood. It sounds like you've taken a thoughtful approach to your system architecture. If it works for you, it works!