Of course the average person will be willing to install a VPN app: all it takes is a bit of internet censorship, blocking access to their favourite services, and some geofencing, where services limit access to them based on IP address.
Just ask people from China, Russia, Ukraine, Turkey, UK, Germany, etc.
When you use services like NordVPN, Mullvad, Surfshark, etc., you're just installing a VPN client, and you're basically just using them as a reverse proxy to hide your IP address (present it as coming from another country). That is the use case you are talking about.
Tailscale is very different. It is about setting up your own VPN so that you can access devices from your home or wherever from the Internet at large in a secure manner.
Tor exists and is far better at providing privacy.
Does that matter? It still shows willingness to install.
Just look at the US - tons of people now install a VPN app like Nord or Mullvad to get around state-level porn blocks. In other countries it's to get around other types of censorship. And to install those apps on something like a phone or laptop is trivially easy.
The use cases for installing Tailscale (I need a home network and I need to be able to access these devices from the Internet) is, I would guess, ~5% compared to the other VPN use case. I'm a software developer, and I don't need it.