Why is WIFI being used more when it is less protected?

In the modern business world where even fast food restaurants are providing wireless access points to their clients, wired internet is just not feasible in many cases. Could you imagine all of the extra money it would cost to have UTP line run to jacks through fast food chains or coffee shops, then patch cables that people can run to their devices. Also it would not be helpful because most people are looking to connect their phones which do not have Ethernet jacks. Between the cost and lack of practicality, businesses opt for Wi-Fi. The same could be said about residential use. For my own home I would love to have UTP ports located in a few strategic positions throughout my home, but the cost to open up the walls and hide the cables is just not worth it when wireless router can give every device in my home sufficient bandwidth. While using wireless is very convenient for my home and many small businesses (especially ones who are renting an office space), it is not without its own issues.
Some of the challenged that are caused by an increasing demand for wireless communications are: Security, co-channel interference, electromagnetic interference (EMI), signal degradation over distances, dead zones, and signal collision. Many solutions have been created to deal with some of the issues mentioned above.

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Security has gone through several advancements, first there was WEP, then WPA and finally WPA2. WEP was flawed and easy to crack, WPA is better than WEP but there is no reason to use it while WPA2 is superior (Bidgoli, 2010). None of these options can protect one from a man in the middle attack, since the packets are being broadcast across radio waves, this can be exploited by a man in the middle attack, the only way to protect against such an attack is to use a VPN which will encrypt the data before it is sent out, therefore making it useless to someone intercepting packets.
To deal with co-channel interference, the best thing to do is use different channels and different service bands where possible. The next thing that can be done is they can spread the spectrum of their broadcast to try and correct this interference, however the tradeoff is the speed is reduced when this is used.
In order to deal with things like EMI, signal degradation over distances it takes a bit of planning before setting up the system. Signal scanning software can be used to test signal strength and etc. before committing access points to locations (roughly 10 meters apart).
Signal collision is another thing that must be considered, this can be addressed with Media Access Control (MAC). This dictates when devices can transmit so that they do not transmit at the same time, thus preventing collisions.

Works Cited
Bidgoli, H. (2010). Mis -Student Edition (11) . Boston: Cengage Learning.