If you really have a fleet of web servers burning CPU and you arne't tracking the costs, then I guess "it works" until someone figures out there isn't any money left in the coffer.
There is a lot of value in working software, and unless your engineering infrastructure expenses seriously outweigh your engineering payroll costs (which does happen, but is hardly commonplace), CPU efficiency isn't the be-all to end-all and focusing on it may well prove to be counter productive. If no one actually cares about your page load times, it may very well be that it doesn't matter. You can spend a near infinite amount of time & resources trying to get optimal performance (talk to someone who does high-frequency trading to get a sense) well past the point where the costs pay off.
There is tremendous value in "it works" that engineers generally struggle to fully factor into their thinking (I come by this wisdom honestly). People have written about this extensively (e.g. https://www.joelonsoftware.com/2000/04/06/things-you-should-...). That said... the notion that you can't fix actually serious and counter-productive problems with the product because "it works" sounds not only counter to Scrum, but really counter to any software development methodology I've ever heard of.