Pretty sure this person is just talking out of their ass. I found one source from four years ago that showed a price difference of about a buck to manufacture. Yes, that is more expensive, but passing that dollar onto the consumer for some USB-C ports on a motherboard seems pretty reasonable, and by now I'm sure that gap has decreased significantly.

I know for a fact that USB-c is about 1.5× mirco-b.

https://www.adafruit.com/search?q=usb%20breakout%20board

Since USB A is not a slave connector that are no comparable boards on adafruit. So I asked Bing AI:

According to the web search results, the cost of a USB-C connector on a motherboard depends on various factors, such as the manufacturer, the chipset, the data standard, and the features of the motherboard. However, based on some examples of motherboards with USB-C ports, the price difference between USB-C and USB-A connectors with the same speed (USB 2.0) is not very significant. For instance, the ASRock B550M-ITX/ac motherboard has one USB-C port and four USB-A ports, all with USB 2.0 speed, and costs around $120. The [ASRock B450M-HDV R4.0] motherboard has six USB-A ports, all with USB 2.0 speed, and costs around $70. The difference in price between these two motherboards is $50, but this is not only due to the USB-C connector, but also to other factors such as the chipset, the memory slots, the audio codec, and so on. Therefore, it is hard to estimate the exact cost of a USB-C connector on a motherboard with USB 2.0 speed, but it is likely to be less than $10.

I dont remember off the top of my head the exact number of conductors, but it has like 22 or 24 very very fine wires in it, that have to be lined up perfectly on both sides of the (comparatively small) connector to be soldered to equally small pads.

So its much more labor and time intensive to make a USB-C connector, compared to a USB Type A, which has big bulky cables and equally bulky (comparatively speaking) pads.

USB Micro/Mini used tiny wires too, but again.. only about 2-4. So far less time and labor to line them up, and even compared to USBC it can still have larger solder pads to connect to due to the number of conductors vs the 22-24 conductors inside the Type-C connector.

And thats just the connectors and the wires. the support circuitry to actually run it is more complex and expensive as well. Which further increases the cost.

And theres just no reason for it, the number of devices that need and benefit from higher speeds USB-C can support are few and far between, and typical motherboards coming with 1-2 type-C sockets is more than enough to support that for 99.99% of the people, and if you are in some very weird niche case scenario where you need a bunch of USB-C ports, you can get a USB-C PCI-Card (just make sure you get a reputable brand one, and not one of the suspiciously cheap no-brand chinese knockoff ones)