I have little doubt that a lot of your lost upvotes comes from a packed home feed. I admit that I can't keep up with the few people I do follow. I only actively give look outs for yours and a few others posts. I don't think your content is the problem seeing as I am here still. While I can't say I've noticed a drop in upvotes (all of my posts are either boom or bust) I have noticed an increase in followers with no upvote from them. The only way I could give you advice is if you aren't enjoying yourself posting. Have fun and love what you do foodie.
(P.S. All of my big post I posted at about 11:55 California time. So about 40 minutes ago from right now.)
I have the same problem with my home feed to be fair. It's hard to keep up with so many posts and so little filtering options. I'm glad to hear you don't think it's the quality of my posts :-)
You're right though! As long as I'm enjoying myself, I'm sticking around no matter what.
This particular post is getting quite some attention, that does coincide with your findings!