A serious deficiency in the introductory physics syllabus

With one lecture left in my non-calculus "College Physics" summer class, I gave the students a choice of covering oscillatory motion and sound or free energy with two applications to biological physics. The vote was unanimously for the latter.

To my surprise, their textbook (the latest edition of Sears and Zemansky's College Physics by Young and Geller) has no mention of free energy, nor do the six other introductory physics textbooks (calculus-based or not) on my office shelf.

A "water cooler poll" shows that nobody teaches about free energy in their introductory class. One grad student said he didn't see the topic at all as an undergrad! We teach students the Second Law of Thermodynamics, but not any of its practical consequences. Stock homework problems consist of ridiculous irrelevancies such as computing entropy produced by a falling parachutist.

Free energy is perhaps the most useful idea we could teach life-science majors, and it provides a foundation for understanding chemical kinetics and entropic forces such as osmotic pressure, polymer elasticity, and the hydrophobic effect. Most of them hear it as a term in their general chemistry class, and even use it to predict the direction of chemical reactions, but they'd have to take physical chemistry to really begin to understand it.

Could someone please explain to me why it's so universally absent from the syllabus as to be excluded from textbooks?