The "home lab" hobby proves their point. There is a large selection of used, reiliable tthin clients for very light appliance use and a wide range of "tiny" PCs (and other architectures) for users wanting as or more capable options complete with power supplies, cases etc and with good community support for mods and upgrades including 3D printed parts. Rugged industrial computers and network appliances are also abundant and increasingly well known thanks to enthusiast channels.
If I bought a bare Pi board I'd need much more than that to make it usable. I'd need to buy, scrounge or make those components. OTOH I can choose from any of many complete and partial prebuilt enterprise quality commercial systems made in vast quantiities and enabled by many options, accessory configurations, 3D-printed community parts.
and parts.
Pi moved to compete in a very competitive space. It's original niche was more specialized rather than being intended as a general purpose PC in a world full of used performant thin clients and tiny office PCs often powerful enough to game or easily modded. Enthusiasts wanting small size but higher performance often assemble small rack systems with each same-form factor tiny PCs.
For example they can quickly, easily and cheaply assemble a main PC for desktop use, a file server and a network appliance of choice. Even a rack or larger case is optional. (I stick my Lenovo tiny PCs together with flat magnets held to their parent component with double-sided industrial tapes like 3M VHB (also used in building Class 8 dry van and other trailer bodies instead of mechanical fasteners).