Honestly those wall dispensers that stick to the wall and get mouldy overtime does scream cheap.

Some higher end hotel in Bali (St Regis and Four Seasons Bali) actually use ceramic refillable soap dispenser.
The dispenser is replaced when new guest check in.

While the plastic waste is pretty much zero, the cost of initial purchase of those dispensers and the cost of refilling and cleaning might outweigh the monetary savings.

Whether this can be implemented in more lower end brand, I doubt it.