I haven't seen use case proposals where 5G replaces home WiFis. It's often referred to as replacing the last mile to your home (i.e., your home router would talk 4G/5G to the operator and create a WiFi in your home). Also, some "small cell" approaches use WiFi and only do the access management using the mobile network.
WiFi on the other hand doesn't have any approaches for wide coverage, cell handover, or any kind of IoT applications.
I'd expect that smaller manufacturers emerge, especially for niche use cases outside consumer mass-markets.
The high frequencies are one of the techniques in 5G that enable faster data transmission. Another is beamforming: instead of broadcasting data in all directions, it is only sent in the direction of your smartphone. The thing is, there's no change for the receiving smartphone (same RF transmission power), just reduction in interference for others.
[edit: thereby, you can have more devices talking on the same frequency without disturbing each other, since they are separated by the "beams"]
Why should it be at its peak? Look at WeChat. If WhatsApp successfully transitions to a platform with payments, business interactions, possibly in-app-ecosystem, then the network effects become even crazier.
Signal on the other hand doesn't even attempt any of that: it solves messaging with no perspective on third-party service integration.
Seems like the mRNA technique is pretty new and simply hasn't been used for anything else before.
The approval processes are still the same, just without the years-long idle cycles that usually slow things down. The end result will be good as any other vaccine you might get.
WiFi on the other hand doesn't have any approaches for wide coverage, cell handover, or any kind of IoT applications.
I'd expect that smaller manufacturers emerge, especially for niche use cases outside consumer mass-markets.