Some generalisations. Bear with me. Either a business sustains itself by its profits or participates in welfare/patronage. Yes, we hope to have periods where we have sufficient reserves to withstand low profit periods, but eventually, either (1) profit becomes the bottleneck to sustain the business or (2) a benevolent force sustains the business irrespective of its profit situation. I assumed (1), because in the case of (2), it doesn't matter what else we do as long as we appease the benevolent force that funds our work. In the welfare/patronage situation, all bets are off; therefore, I assume that we don't find ourself in that situation.
Yes, in some situations, "just keep it working" will mostly satisfy a customer base, for a while. It might satisfy enough of your customer base for more than long enough to satisfy your personal needs for money. On average, however, customers want more in the long term.
One aside: I did assume in this whole article that we find ourselves in the context I stated, because of how frequently I see it. In those situations that don't match this context, this particular opinion might have as little as no value.
Yes, I have remained a customer of some services out of inertia or genuine satisfaction. This happens, for example, when it costs so little to remain a customer that I don't need to optimise that part of my life. I find value in remaining a customer on autopilot: just keep everything working, don't change anything I use, and so on. Eventually, however--and it might take years--a competitor offers me something better-enough to get me to consider switching. Or perhaps my financial situation changes and it now becomes worth the effort to reconsider my choice. Or perhaps a friend tells me how much happier e is with another service, and convinces me to switch. Complacency represents a risk in this environment. (A risk doesn't necessarily become a problem.)
(Incidentally, I think about improving performance like adding features. "We can now handle load that we couldn't handle before." or "We can handle customers that we couldn't handle before." or "Customers can trust assets to us that they couldn't trust before.")
And yes, in spite of the unexpected alignment that I've tried to highlight here, we might see more perfectionists among programmers than among business people, and my observations here have no real bearing on that.