For companies, WFO fosters collaboration, and further Innovation. Things may also move a bit faster when everyone is available at the same time.
WFH is good option for a lot of employee, but it kind of makes it impossible for the above things. When company would like to focus on generating more profit, why would they prefer WFH?
Also, please don't generalise everything with your 'zero' real experience (without full-time permanent experience), and that too at an HFT company. If you just want continue to write code monotonously, WFH will be ideal as well.
Hybrid should be the way to go.
PS: Whenever I'm in Bengaluru, I usually go to office everyday, and I like it. But I also have the freedom (fortunately) to take WFH whenever I want for any number of days - and am remote currently.
You spend ~1/3 of your peak life with strangers, so wfo also helps in establishing a good rapport with them.