“memory is free, so find more stuff to cache to fill it”

As long as it's being used responsibly and freed when necessary, I don't have a problem with this

“we have gigabytes of RAM so it doesn’t matter how memory-efficient any program I write is”

On anything running on the end user's hardware, this I DO have a problem with.

I have no problem with a simple backend REST API being built on Spring Boot and requiring a damn gigabyte just to provide a /status endpoint or whatever. Because it runs on one or a few machines, controlled by the company developing it usually.

When a simple desktop application uses over a gigabyte because of shitty UI frameworks being used, I start having a problem with it, because that's a gigabyte used per every single end user, and end users are more numerous than servers AND they expect their devices to do multiple things, rather than running just one application.