It's very nice of them. No one (not Microsoft, not Dell, not HP, not Compaq) offered adaptors or cables at any type of discount when USB first rolled out in the late '90s.
Did those manufacturers make devices with only ONE kind of connector?
Well debunked. Of course they didn't (and if they did, you'd go a competitor for your Windows-compatible PC). If anything, they went to the opposite extreme and were too conservative about dropping legacy connections.
Even the thinnest and lightest laptops of the day came with more than just USB in the box: I (mistakenly) bought a Sony Vaio PCG505 circa 1998 - a tiny laptop (the 11" MacBook of its day). USB, Firewire, IRDA and PCMCIA on the main machine and (cover your ears Tim & Jony) it included a port replicator with VGA, PS/2 mouse & keyboard, parallel and (I think) RS232 (people used modems in those days). Gave up on it because by the time you had packed the port replicator (included), the external CD drive (included) and the external floppy drive (included... someone get Mr Cook a glass of water, please) you might as well have packed a bigger laptop...
If you include desktops and small-form-factors (like Mini-ITX) VGA and PS/2 mouse/keyboard sockets are barely gone today (and you might even find a parallel or RS232 header on the motherboard). Back in the late 90s, PCs had been sporting unused USB ports (poor/nonexistent drivers in Windows 95) alongside everything else for a while before Apple got things rolling with the original iMac. Even the famously USB-only iMac included Firewire and Ethernet.
Oh, and it was a major step forward to have those thin, light USB cables with their tiny connectors after the bulky parallel and serial cables (seriously, RS232 needed about 5 wires but usually had a huge 25 pin D-connector on the modem end, full of pins that used to do things on a teletype - and don't even get started on how bulky SCSI cables were).
There's never been a connector that aimed to do everything quite like USB-C, so there's never been the opportunity to do something quite as silly as dropping all other standard connectors (including charge and external display) and replace then with a new connector that still needed dongles or replacement cables for the vast majority of peripherals still being sold.