Make multiple tiers of mixers.

Almost everything else can grow with your tech level. It is kind of immersion and factory space breaking when there are cement mixers that look like it that can become level level 3 but it is stuck the whole game as a tier 1 machine with limited throughput.

At least add a tier-2 Mixer. I don't care if it's larger, as long as it's more efficient than the tier-1 one (for the space it occupeis and the labour need). It is indeed very silly that you can upgrade everything else, except non-cement Mixers and Molten Channels.