I never spent as much time as OP on this but I did collect a lot of data during peak quantified self. I liked having automatic data collection and being able to see trends, for example. I stopped because of a few issues, not related to time:

* Hardware companies went out of business, stopped supporting devices, etc. It became obvious that there was no long term commitment to make good quality hardware that lasted a long time.

* Many devices and/or data collection was consolidated big, data hungry companies Google and Apple. Competitors have similar anti-consumer uses of data. I don't want any of these companies to have my data.

* Related to the last one, limited to no offline or local only data collection.

It is very hard to gather most of this data with off the shelf hardware and keep your data private.