I can tell you having been responsible for the aspects of a TINY scale in comparison button, about 30,000 units a year, that buttons are fucking hard man! It's so much harder to make a button than an entire PCB. You wouldn't think so, but you need to be GOOD at injection molding, stresses, DFM (design for manufacturing), cost analysis, generally know ALL the options to produce something, production tolerances and more just to talk to the actual experts in those fields.
Other poster is correct, it's a big deal, and it's why screens have replaced buttons in cars. It's so much cheaper to make a screen. Which is funny because as an EE, I judge a new vehicle first by how many buttons they still have.
As an electronics hobbyist who operates at an even smaller scale (where the cost of a pushbutton itself is trivial), I could not agree more strongly with this. Physical buttons are, counterintuitively, an absolutely massive pain in the butt from a design point of view. I tend to use touch sensitive pads instead. It makes the firmware more complex but the physical design so much simpler.
Other poster is correct, it's a big deal, and it's why screens have replaced buttons in cars. It's so much cheaper to make a screen. Which is funny because as an EE, I judge a new vehicle first by how many buttons they still have.