"Humanity grows exponentially, food production grows linearly" has not been debunked. People have starved in the last few decades, and we barely managed to avoid a widespread catastrophe through a big one-time upgrade to the best farming techniques known. How many other improvements are left before we reach biology's productivity limits? How long until we run low on natural gas to make fertilizer, having long since mined the pre-existing fertility from the soil?
Almost every case famine during last few decades had to do with some kind of local conflict (e.g. local gangs interfering with delivery of food aid) as opposed to resource shortage. Developed countries produce much more food than they need and then consume it in a very inefficient way. Growing grain and using it to feed livestock as opposed to consuming grain directly is one such example. Earth could comfortably support much large population than we have now.
Being both a carnivore and a big consumer electronics junkie I can relate to your argument. I was mostly answering to parent poster's comment about people starving. However I'm a big believer in technology being able to overcome that kinds of limits. Here's an excellent essay illustrating how 15 billion people could be supported at the level of American living standards:
http://www-formal.stanford.edu/jmc/progress/index.html
(As a nice bonus, this is written by John McCarthy, the inventor of LISP).
