Can an enterprise survive without using Properietry softwares?

Can a large company (Say, a Chain of hotels) survive without using Proprietary softwares? Use Only Free Softwares?
As a Techie, I see the world of companies as of only two types:-

Type1: Makers:- Companies who makes products related to technology (Like hardwares, OS, Compilers, Applications, ERP/CRM) like Microsoft, Oracle, IBM, Infosys
Type2:Users: Companies which does not know (Do not want to know), How a software works, rather it should have a nice front-end (I mean user friendly) and It should be reliable, If low cost then better. like ICICI bank, Appolo hospitals, Cafe coffee day, Arcelor Mittal.

I have some rough idea that, for a Type1 company, Moving completely out of Properietry softwares (Windows/Mac, and applications developed for these platforms) is possible though bit difficult. We have OS/Compilers/IDEs/testTools/Productivity softwares which are free and open source. I want to discuss, What we can't get in Open/Free softwares? What is that keeps us not going for these softwares? What all problems Type1 company can face If they want to move out of Properietry software?

For Type2 companies, its still a long time to get Free/Open source as It takes lot of technical effort to get Open source integrated and customized for their requirements.. Comments Please..?