Muc-Off especially. I mean props to them for making their shit biodegradable (if it actually is) but I have seriously not encountered anything from dirt to effluvial grime that a spray bottle with water/dish soap mix and a rag didn't take care of it brilliantly.
Like the only thing is really, really mucked up cassettes or sprockets and chains. Chains clean really easily with steel wool and the really, really mucked up cassettes just get tossed in vinegar for a bit and scrubbed with steel wool.
like half of all specialty cleaning products could just be dish soap
Yep. and tougher spot treatments can be tackled with vinegar + baking soda which is more effective than most harsher solvents. Dawn dish soap is more than enough to clean a bike frame, but a generic degreaser will come in handy for cleaning the chain. Absolutely no need to pay for expensive cleansers marketed to cyclists. Don't buy bike branded grease either, they just rebrand marine grease and sell it for a huge markup.
I've bought some generic machine grease to grease some wheel ball bearings and while the tin says "applicable for everything but ball bearings" the results say exactly the opposite