I nearly triple majored (or a minor) because I took Lit classes for fun when doing my Bachelors. Due to the impacted nature of that school now, I don't think it would be possible to duplicate what I did. Sometimes, for me, having a bit of structure helps focus on an interest - undergrad it was literature (beyond other courses, work, and being social - not sleeping much was I guess helpful at the time).

When I spent about 8 years living in a remote area with a lot of old mines, etc. exploring rocks, having a mining claim, etc was interesting and it was not directly related to work. So, trying Geology made some sense because I had an interest.

Yes the near Lit minor and my second Bachelors (chemistry) were literally for fun - but there was a roundedness to not just staring at computers all the time.

Different people have different interests and approaches.

Also costs when I was doing the initial schooling wasn't as bad as it is now (a TAing job, working in a lab, and maybe some part time tech support) covered most bills. Rent, tuition, and other expenses were under 10k for the year - even at a UC - yes this was awhile ago. My step-daughter is looking at closer to $30k a year (give or take) for a CSU.