But that's not how the argument is used in practice. In practice this argument is used to justify bloated apps, bad engineering, and corner-cutting. When people say “users don’t care about your tech stack,” what they really mean is that product quality doesn’t matter.
Yesterday File Pilot (no affiliation) hit the HN frontpage. File Pilot is written from scratch and it has a ton of functionality packed in a 1.8mb download. As somebody on Twitter pointed out, a debug build of "hello world!" in Rust clocks in at 3.7mb. (No shade on Rust)
Users don't care what language or libraries you use. Users care only about functionality, right? But guess what? These two things are not independent. If you want to make something that starts instantly you can't use electron or java. You can't use bloated libraries. Because users do notice. All else equal users will absolutely choose the zippiest products.