Too bad they were too lazy to learn about USB-C, and the benefits it provides (including being drop dead simple to adapt to USB-A).
That's now how product purchasing works. It's your money, your needs, your wishes, your product. My grandparents are in their late 80s and have used Macs the exact same way for a very long time. They still have an ink jet printer hooked up to their Mac via USB and they didn't want anything fancy or to have to change anything about their set up. So they bought a MacBook Air. My aunt bought one because the guy at the Apple Store said it was the best for her needs. My mom got one to replace a very old Mac Mini because she uses the same USB mouse she didn't want to replace. Yes, you can get adapters, but in the real world people buy things based on their specific needs and wants and not in line with what a company wants you to believe is ideal.
If I had to buy a Mac based on the current line-up, I would probably go with a MacBook Air myself. I charge my devices from my MacBook Pro constantly—it's just always there so it's faster than plugging into the wall. I keep a flush USB-A drive as a back-up drive in my MBP at all times. I still use my MBP's SD-card slot reader. It's how my CGM connects to my Mac and uploads to the cloud. I could see conforming to the changes of the all USB-C MBP (and other compromises like keyboard and glued in battery and loss of SD card reader) if the prices were more reasonable. But the entry level has a weak processor, and then the prices go up steeply on the TouchBar models. For me, the MacBook Air actually has more "pro" features for me in that it has the SD reader, two USB-A ports, and what I consider to be a better keyboard. I know the processor is weak esp compared to the new 8th generation options on the MBP. And I love a good display, so I'm not arguing that the MBA display is good. But each consumer has different wishes and needs. You could educate me all you want, and it wouldn't change that.
Sometimes like with the original iMac there are growing pains when it went all-USB. But the market was flooded with USB products very quickly after that, and the prices came down quickly. I remember going out to Costco after I bought a Bondi original iMac and could easily buy a USB printer off the shelf at Costco. With USB-C you're still limited on options and you're still paying a premium on peripherals. And no flush flash drives, either (although I know that's quite niche). Even Apple is still selling Lightning Apple pencils and sells every single iOS device (which is hundreds of millions) with USB-A ports on the other end of the Lightning cable. They have embraced USB-C quite haphazardly (by necessity no doubt due to the existence of Lightning).
Forgot to mention: All of Apple's desktop computers, including brand new models like the iMac Pro, have USB-A ports.
So Apple realizes customer needs and wants for this. On the laptops I guess it's a matter of esthetics and thinness. Plus there's some element of "purity" which I guess goes along with esthetics. I remember seeing a T-shirt over a decade ago with the USB, FireWire, and Ethernet logo. It had some caption about eschewing the legacy—I forget what it said. The point was that at that time, it was "pure" to just have those three ports. Now it's "pure" to just have one. And eventually it will be pure to have none at all.