Thanks for the link. Although it's not directly comparable since bitnodes.io show number of total reachable nodes in last few hours while monero.fail shows total reachable nodes in last 2 weeks.
Perhaps a more fair comparison would be against
bitnodes' Global Node list.
Monero is the Tor of currencies while other altcoins act like a VPN.
I wouldn't say altcoins are like a VPN at all. Many have even worse privacy than bitcoin does. Just take the biggest altcoin Ethereum as an example - they use an account based model rather than an UTXO based model, meaning all your ETH transactions (and all your stupid token transactions too) are all intrinsically linked together.