Just don't rely on centralized for-profit entities, rely on stuff produced by non-profits and foundations, that you know isn't gonna screw you over as soon as they need money.
What do you use that fits that philosophy and offers the basic functionality (NAT traversal, Magic DNS, failover relaying) TS provides?
What makes you think we'd be better off building a competitor to something open source if it has all the features we want now? The reason we don't see open source competitors to big products is not because people are too dumb to try it. It's because it's way, way harder. It makes way more sense to Fork and work from there while we're still getting this momentum from Tailscale.
If you think Headscale is going to have problems keeping up with a private Tailscale, good luck rebuilding Tailscale.