If you consider the entire cost, yes. Every BOM item has a huge cost associated with it, and it's price only a small fraction.
Consider that for every item you need to:
* secure supply for the next 10 years or so
* organize purchasing and put it into the supply chain
* design assembly instructions, teach workers how to assemble it
* design and implement testing procedures
* design and implement diagnostics to figure out which specific component has failed
* maintain it and keep it available for your service network for the next 10-15 years
* deal with unexpected failure rates and be ready to re-design in case of problems
* also, every knob is actually not one component, because it needs to be connected to something, which implies wires and connectors (the most problematic components in electronics) and multiples all of the above several times.
Look at it this way and suddenly you really want to minimize the number of individual components and replace them all with a single touchscreen. Especially given that you can then deliver crappy software and the market will bear it, because we have been trained to expect and accept crappy software.
But I do agree that the marketing appeal is there, too, although I think some people are waking up.