I wonder, do you think the Bitcoin network will survive if all the network nodes are non-listening (outbound connections)?
Well, you need at least a couple that do listen, otherwise there would be no nodes to connect to from all the other nodes (with only outbound connections). But if there were only a few of such listening nodes, it would mean we (as a network) had a huge attack vector and it wouldn't be good for decentralization either.
It also limit how many nodes could available on network since few node (which listen) certainly have upper limit of incoming connection.
But usually, it's the user's network, ISP or system that's hindering inbound connections.
Additionally, lack of user knowledge to configure port forwarding/firewall or assume running Bitcoin Core is all they need to do.