I've looked at this thread subject everyday since it was posted thinking there is not much I can add. Many great and solid points have already been established highly supporting the highly successful opportunities with these "big companies," like Amway, Mary Kay, Herbalife, Shaklee, Forever Living, and FreeLife. Yes, I know there are many more, but we all get the point.
To answer the original poster's question, the resoundingly true answer is,
ABSOLUTELY YES!!
I believe today, one has a greater chance at a long term, leveraged, walk-away income; investing their time, effort, and money in a solid big company than a start up type. Why? Simply because everything is already established without having to deal with the "growing pains" of a newer company. I could go on and on about what a larger solid company has to offer but space and time are limited.
The key to overall success is a business mentality, vs. a consumer mentality, understanding this is a "PEOPLE" business, not a PPC, Google Adsense, numbers, online vs. offline, business. And, no matter what one chooses one must be willing to learn new things and apply them through "WORK." Thus the famous net-"WORK" marketing name of the business. Anything worth having is worth working for. The only place "success" comes before "work" is in the dictionary.
I say again, if one wants a business and extra income, get off your a$$...butt, quit wishing, there is not easy way or "secret," and go out there and "DO IT!" (BTW, that "is" the secret!)
To summarize,
Can you really make it big in older companies?
The resounding truth is.....ABSOLUTELY YES!!