If your software is slow, it's probably because nobody was incentivized to make it not-slow. There's plenty of software out there that's fast, but if perceived slowness isn't costing someone money and making a company's life harder, it's unlikely to get solved.
Two examples:
1. My gmail can be horrifically slow some days. It's not because Google is unable to make IMAP sync fast, or that there's some inherent protocol limitation for what I perceive as 'being slow.' I run my own mail on DigitalOcean and I consistently am faster to sync large quantities of mail relative to a gmail address. Google isn't incentivized to make their free service faster, since they aren't losing money when I complain that gmail is 5 seconds slower to sync similar or lower volumes of mail compared to my own personal server. Note: I understand why there's good reasons for this.
2. Netflix and Youtube have a ton of backend servers and services that can be selected to immediately stream to any given computer on the planet, should someone click on a video. These are extremely highly performant and allow basic compute-heavy loads to be spun up at literally the click of a button on a webpage. It is specifically some engineer's job to get delivery windows on videos down as much as humanly possible because the organization makes more money from users (people tend to avoid services with huge delays, thus decreasing ad / subscription revenue) and spends less money if they aren't wasting compute.
Software speed is entirely dictated by the incentive structure around it. If you want to complain about why software is slow, it is useful to understand who's problem that is, and whether perceived performance is enough of a blip on the radar to be worth investing someone's time in it.