The Cortex-A53 is really weak. I wouldn't want to run an office suite on that either. Oh, and the Pi 3 was VERY limited by RAM.
"most office people, students, and so on" pretty much always do browse lots of modern websites, at the same time as running an office suite, audio player, and more stuff.
The A72 is really the "minimum viable CPU core" for desktop usage. Anything with less single-core performance is absolute hell and suffering.
Not true. I barely notice any difference between my Orange Pi 3 (4x Cortex-A53 @ 1.8GHz) and my Ivy Bridge workstation, when browsing the web, and things like that.
I don't run a heavy weight desktop though.
The only noticeable thing is some increased latency (mainly due to storage speed limited to 20MiB/s read speeds), but animations and scrolling and basic stuff like that are pretty much smooth. I could easily run the system from USB attached SSD (which can achieve 15-20x the speeds of the SD card), and that would massively improve app startup speeds too.
Also video playback sucks, but that's mainly due to software support, not a hardware issue. It's a chip meant for TV boxes after all.
I wouldn't use it to compile programs, but office work? I can imagine that easily.
Even the Pi 3 was already good enough for most of those use cases. The main exception being browsing modern bloated websites.