You’re digging your heels in by cosplaying proletariat. If someone wants a separate computer, they’ll get one. It’s not a matter of not being able to afford it. Maybe their work computer is better than the one they’d buy themselves. Or maybe “afford” in this case (as usual) means that they can’t justify the cost when they could spend the money on something else, and are happy trading the work-life balance.
But don’t pretend that this isn’t a consensual arrangement.