Why is WIFI unlimited whereas Cellular data is limited ?

A single Wi-Fi access point generally serves a few people in a home or business. A cellular base station may serve thousands of people. Ensuring that capacity is adequate for sudden spikes in usage requires that the base station not be overutilized during non-peak times. Charging for data transfers on a monthly basis allows cellular operators to deter subscribers from using their network as they might use a residential Internet connection, helping to limit congestion for the majority of subscribers.

Additionally, powering Wi-Fi access points is generally the responsibility of a home or business owner, while electrifying a cell site and all its components is the responsibility of the cellular operator and/or the cell site lessor. Someone has to pay the bills.

Is WIFI really unlimited data?

WiFi is not Unlimited. Yes, most of the technology providers have an impression that WiFi is Unlimited Free Internet while Cellular Data is Limited Paid Internet.

A smartphone with Cellular data can also be used as a WiFi Hotspot which doesn't make the WiFi Unlimited.

WiFi or LiFi network Which one is more secure? Why?

Why Not Distribute Wi-Fi Over the Distributed Antenna System (DAS)?

WiFi is similar to LAN, except it uses Wireless signal to connect devices, one of which would be a router which intern will be connected to a modem with High Speed Internet.

A cellphone receives signal from a tower in a one-to-many basis. But here, the tower will be the router which routes cellular services to your device in an independent network.

Now, in some places, they offer free WiFi services which is limited in many aspects. They are however, not giving that for free. You get free WiFis at Cafe, but some people pay for that along with the bill, you wouldn't notice. Most places offer free WiFi because it is an interesting place to advertise and even get money of you offer Unlimited WiFi for a Limited time.

Internet is a commodity that has cost like laying underwater cables, managing servers, wages, etc.. Some think WiFi is Unlimited because most people go with Unlimited plans for their internet connection. Even the some phones asks the device to be connected to a wifi network to download updates even if the mobile has unlimited cell data. That is just how some clever minds made impression that WiFi is unlimited.