Tailscale has raised $160M

IMHO they should be a good steward and toss the Wireguard guy a mil considering Tailscale is pretty much Wireguard with a GUI on top.

This is not correct. Wireguard establishes a tunnel between peer A and B, and its simplicity stops there. Tailscale does tons of complex networking, filtering, nat traversal, DNS, file sharing, etc. Wireguard is a small part of the codebase today, which has grown a lot.

It’s a bit like saying Dropbox is just a GUI on top of TLS.

Most of this was successfully done 20 years ago by tinc, which is a project written by a couple of European guys in their free time. It even supports routing traffic through other peers and does peer discovery just like BitTorrent (but before BitTorrent even existed) — there is no need for a central server.

What tailscale has over it is hype, lots and lots of hype. Also a much more well thought out, and arguably more secure VPN protocol underneath, which is why GP's comment is on point.

If it's hype, it's not hype the way you're thinking. I've shown Tailscale to a lot of people (this is less salient now, when pretty much everybody uses Tailscale) and the most common reaction I've gotten is "holy shit". It is spooky simple to get working, and it's spooky simple to go from a working installation to a VPN configuration that would take many many hours to replicate with pre-existing tools.

There may be VPN nerds out there who think there's nothing special happening with Tailscale, but I submit those nerds haven't spent a lot of time dealing with the median, replacement-level VPN configuration prior to Tailscale. I'm a pentester, and so I have had that pleasure. Tailscale is revolutionary compared to what it replaced.

My only technical complaint with Tailscale is that its hole punching doesn't seem to work with some common CGNATs/double NATs when both endpoints are using them, and then traffic ends up trickling through their public proxy servers, while running your own is kinda annoying and not recommended or documented.