What, do you have a single bit of proof for this? I fail to see how making anything with a circuit on it can be cheaper than a piece of plastic, blu ray is less than a dollar each including the content on it i.e. not a blank disc
nemo37 posted the link earlier, but here it is:
And even then, there are not many options when it comes to cartridges or discs since you have to consider the size of the Switch.