Where I think he's off is the assumption that dependencies are the primary reason for performance problems. It's true they are a part of that problem, but it's not the way he's thinking (IMO).

What causes dependencies to be performance headaches is the fact that just like everything else, they aren't a priority when it comes to performance analysis. And the bigger the set of dependencies or the framework, the less likely those devs have spent meaningful amounts of time tuning for performance.

These abstractions absolutely could actually be a shortcut to high performance, if there were good incentives to make it so.

There are actually a few examples of this. For example, nothing you could do will be anywhere near as fast as the GMP when it comes to handling big numbers. Handling big numbers fast is the name of the game for that library.

But those deps are the exception and not the rule. And that's the problem. It's not that dependencies couldn't help make everything faster. It's that like a regular application, dependencies are incentivized to bring in more dependencies to accomplish their goals which ultimately nukes performance.

In his video, he talks about how the AI made a base64 encoded json stream. Of course that's horribly slow. But you know what isn't? Protobufs, flatmaps, or and a slew of binary serialization techniques and libraries. And those libraries will easily and efficiently do the work just as well, probably better, than what you could accomplish by handrolling a binary protocol.

He also talks about the good old days (bad old days?) of hypertuning for caches, pages, and memory utilization. This is a fun practice to do, but in my experience performance problems very frequently aren't often due to any of these things. More often than not, it's the fact that someone is doing an n^2, n^3, or n! algorithm and nobody caught that. Generally speaking, if devs kept their software in O(1) or O(n) computational complexity, that'd solve a huge amount of the jank that modern systems experience. All that requires is collecting and reading profiling data to identify these hot spots in the first place.

And that, IMO, is the primary source of failures. Devs are not typically collecting profiling metrics. They are more often than not just guessing at why something is slow and fixing what they think might be the problem. And if that problem lay in a dependency, well, often rather than fixing the dep devs will work around it.

I've actually dealt with exactly this problem with, of all things, the microsoft JDBC driver.