I think you and the parent comment are both correct. Engineers who are skilled enough to do this type of analysis are expensive and another VM/Instance is a few hundred a month at most.
At the very small end of the scale this is very true. It doesn't take too much traffic volume to make it worth it though. It's just difficult to make anyone care. It doesn't take a particularly huge amount of traffic to make it worth spending a few weeks of engineering time to save $50K+ on annual hosting costs.
I think you’re considering only literal cost, and not the opportunity cost (which is typically much higher, and what you’re using to make investment decisions). Suppose you’ve an engineer and they’re paid $100k. Now you’d be tempted to say that anything that takes less than six months and saves more than $50k is worth it. But that’s not true at all. For one, that engineer is actually worth much more than $100k/yr to the company; it costs a lot more to hire and keep that person busy (recruiting, training, an office, a manager, product managers, project managers, etc.). But more importantly: what are the other things they could be doing? Small companies are rarely thinking about micro-efficiency because they are trying to change and grow their products. If this engineer is able to build a feature that will help them grow X% faster, that can have a massive multiplier effect on their prospects (and valuation, for which that $50k saving makes zero difference). Those are the things you’re comparing against, which is why the opportunity cost bar for pure $$ saving improvements is often much higher than it seems.
