Or to put it another way that will strike accord with a different audience. At what point do I stop refactoring my code and say, "This is good enough"? When do I say, "I've achieved my goal and as imperfect as this is, I'm going to start concentrating on new things".
Optimising revenue is not desirable. Making enough revenue to achieve your goal is what is desirable. Once you've done that, you should concentrate on new goals. However, just like refactoring code, you may find that you need to go back and revisit something in the future. "Not now" does not necessarily mean "Not ever". It just means that I'm putting this aside until it makes business sense to do it.
To complicate things, though, just like programmers have to be the ones calling the shots about whether or not something needs to be refactored (they are the ones who have the required vision and experience to know), marketing people need to be the ones calling the shots about these kinds of things. If you don't trust your programmers to make appropriate decisions, then you have a huge problem. The same is true of marketing people.
Fixing that trust issue (either by placing your trust in the people, or replacing people who are not worthy of trust) is hyper difficult, though. It's one of the reasons organisations run around doing ineffective things instead of fixing this kind of root problem.
Considering something "optimized" is always going to be a struggle of almost perfectionism (even for myself and my own website haha).
I think you should always be critical of what would be better use of your time: optimizing vs getting more (targeted) traffic ;)
I think if you think small tweaks are all you have left that you need to consider how can you make your website specific to each persona you have on or even dig through which type of people could benefit from your product even outside of what your currently targeting.
Rule #2: The universe is not constant: Screen sizes change, browsers, screen types, technology, new competitors come up changing people's expectations, people's tastes change, you expand into new demographics/demos/sales channels which react differently than existing demographics/sales channels, etc.
Ideally this work is done with a marketing/programming/operations team all in one, so all aspects are considered, with their trade offs, to forward on a collective understanding of solving user pain points.
I am not speaking optimized in terms of perfection I am talking about optimized in terms of revenue generation.
At a certain point your offering is it's offering, people found the maximum value out of it, and making it easier to use or testing different ways of delivering that functionality is just adding on lipstick.
At what point does it make sense to pursue other revenue models or strategies rather than squeezing out another 1-3%
I am bringing this up for a reason -- my company is going through this very thing
At what point do you consider an experience "optimized" and say we just can't squeeze anything else out of this?