Well, to get back to your origional thesis bulldogg, I disagree with you.
The army itself (not congress) has actually tried a number of times to get rid of the M-16 and the army (not congress again) has decided to stick with the M-16. In the 1970s there was the Special Purpose Individual Weapon program which was terminated. And again in the late 1980s you had the Advanced Combat Rifle contest. The ACR program tested a Colt highly modified M-16, a falachet rifel, the H&K G11, and the Steyr Aug: the result was that none of the rifles met the 100% improvement over the M-16 demanded by the army.
The end of the ACR program began OICW program which continues today, still with not a millitary-industry-congress spending spree in 50 years.
So you see bulldogg, replacing the M-16 family is nothing new. If it was motivated out of some kind of corporate greed conspiracy we would have gone through 2 or maybe even 3 rifles already! You seem to forget when calling this "constant replacement" that the M-16 is older than you are, bulldogg! When the M-16 was invented that box you're using to type to me would take up a whole building and the TV came in two colors, black and white.