"Whether or not an egg is produced is decided ever 256 steps you take, so if you're standing still, nothing will happen."
"Aside from what is said about your Pokemon, the chance an egg has to appear every 256 steps can be determined by what two Pokemon are being bred:
If the Pokemon are the same species and have different OTs, the chance is 70% (88% with the Oval Charm)
If the Pokemon are the same species and have matching OTs, the chance is 50% (80% with the Oval Charm)
If the Pokemon are different species and have different OTs, the chance is 50% (80% with the Oval Charm)
If the Pokemon are different species and have matching OTs, the chance is 20% (40% with the Oval Charm)"
https://pokemondb.net/pokebase/51679/how-long-does-it-take-for-an-egg-to-appear-at-the-daycare#q51679
Your Ditto didn't stop producing eggs, it probably just had a low chance of producing eggs. I can't speak for that because I don't know the OT's of all your Pokemon. So yeah, literally just do more riding around on Tauros to get more steps.