Orlando is expensive because it is worth it. Actually there are things in Orlando that are expensive and many things which are very affordable. The parks here can be very expensive and so can some hotels but you can do them on a tighter budget with a little research, planning and flexibility.
Housing in Orlando can be very affordable or extremely expensive as shown below. Much of the city has homes in the $300,000 range and so do some of the surrounding cities.
The largest employers are Disney and governments neither of which are paid enough to live in very expensive housing. Rest assured they know how to live here comfortably. Venture just off of the tourist path and you will no longer think, Why is Orlando FL so expensive?