The problem is that feeds quickly get filled with garbage content that is just there to get upvotes. To get those out, I only would have to follow the few accounts who systematically bring good quality content that also interests me and that I actually want to take the time to read, or the people here I connect to and have become friends. Both those are in the auto-upvote list anyway.
The way I see it, Auto-Upvotes is what is helping Hive way more than it is harming it, similar to how in Splinterlands people running a bot to play for them is keeping it alive. The reality is that the time requirement to do everything manually is not realistic, at least not with the level of quality of content & gameplay right now.
If Hive was full of addictive content (like many other social media) & Splinterlands was a super addictive game that people want to play 24/7, the manual curation and manual play would make sense. This is simply not the case.
If Youtube had a hive-like upvote system, I would be 100% manual curation and come short in voting power. Manual curation on Hive is pure torture and a complete waste of time.