Because growth is most of the time translated as acquiring more users/customers. Eventually making more money out of them.
Somewhere in the distant future, making money becomes cost saving, this is when companies start thinking about how can we cut the cost and such projects/explorations become relevant.
Even then it is not easy to sell as a project. Because there are so many unknowns, discussion goes like:
me: hey, I see spikes in CPU/mem usage, want to investigate why.
Product: is it important now?
me: I don't exactly know, but it might end up saving our instance costs.
Product: how many instances we are talking about?
me: I don't know yet how big is the problem, depends on what would be the result
Product: how long does it take you to do a research?
me: I don't know what is the problem yet, so I can't evaluate how long it takes to find it.
Product: maybe we shouldn't do it then?
me: (again) but it might end up saving our instance costs.
Product: ok, do you think you can finish investigation in 2 days and share with me timeline and metrics this project would improve?
me: ok, let's forget about this shit we made. what is a next "metric improving, highly visible" project we have?
Product: cool, I want you to work on this super exciting "Move button from Page A to Page B" projectIf you always do the obvious things, you’ll end up as a mediocre company that might not survive. If you say yes to any project that comes to mind, you’ll end up burning all your money and end up with endless projects. It’s important to strike a balance and try to find the right investments others don’t see to create a competitive advantage.
It helps if the culture allows for that. The questions still are relevant, you just don’t always need precise answers, Probe 100 instances and see if it surfaces more than once. Set up a list of things you think you’ll need to be doing and an initial proposition what you think might change. It’s the PMs job to then convince others that it’s worth taking the risk.