> So if bigcorp wants OS X WireGuard support, they should be able to pay handsomely for it.
Who says they're not? A lot of the companies on https://www.wireguard.com/donations/ ship their own macOS software. Just because the Wireguard Mac app is free doesn't mean nobody's giving them money that's earmarked for Apple development.
Video editors, designers, and sound mixer are a few example professions where users mostly use Apple products. Most companies have designers.
Additionally, companies don't choose their whole software stack based on their VPN solution. They would just change a VPN solution if it's incompatible with what's there.
By now, video editors and sound mixers are heavy windows users, because there's no halfway endurable Apple machine that you can purchase that supports 128GB of RAM and 8+ CPU cores and NVIDIA CUDA. Because like it or not, almost all video editing plugins use CUDA for acceleration.
And yes, the users are smart enough to see there’s an iOS client so you can’t just tell them “it’s not available”.