It's not just software development, it's everywhere. Devices are cheap, people are expensive. So it's not lazy, he's being asked to put his expensive time into efforts the customer actually wants to pay for. If having him optimize the code further costs way more than buying a better computer, it doesn't make sense economically for him to waste his time on that.
Is that yet another example of how the economy has strange incentives? For sure, but that doesn't make him lazy.