While there are alternatives to such attacks, active attacks require a greater investment by the attacker, and in some cases aren't practically feasible without being detected by the legitimate network operator.
Anyone connected to the network you are connected to has the ability to route your traffic through themselves and sniff/manipulate it.
Ultimately, if your threat model is to protect against the actions of a state actor who likely does not have active control over your network, but might be able to passively listen, then ubiquitous encryption helps a lot with defense in depth.
A more mundane case is free wifi at an airport. Someone can set up a hotspot with the same SSID and act as a MitM, but it's not undetectable. Here, encrypting application traffic is just one solution, and not necessarily the best one, but you shouldn't be relying on only one layer of protection.