I'm not sure what the author was referring to, but in our stack ES is the only non-serverless tech we have to work with. I know there's a lot of hate in HN around serverless for many reasons but for us for several years, we've been able to scale without any worry of our systems being affected performance-wise (I know this won't last forever).

ES is not this way, we have to manage our nodes ourselves and figure out "that one node is failing, why?" type questions. I hear they're working on a serverless version, but honestly, I think we will be leaving ES before that happens.