I find it funny that the OP waves as riders go by but wonders why they aren't concerned about his flat. If he were in trouble, he wouldn't be waving, he'd be asking for help.

Plus, if this 'happens a lot", the OP should own up and prepare properly to make sure it doesn't "happen a lot". I make sure to carry more than one spare tube, a pump and proper supplies. I expect that of myself so I'd expect it of others. Knowing the situation, I rely on myself and never fret over why others didn't make me their responsibility. A serious mechanical is different, but a flat? It's par t of riding and for me to "expect from others", just plain silly IMO.
The guys that offer help do so because they are being very kind not because the flat victim should expect it.

I've helped tons of riders with flat, mehcanicals and even providing them with tubes. I gets expensive after 20 tubes or so. I've gotten to the point of thinkig, if they don't take care of their own problems, why should I make it mine?

And certainly if I ride by and you honestly need help, you better do more than just wave! If you need help, it's your responsibility to ask me, not the other way around.

Maybe I should go for a drive on the freeway till my truck runs dry then expect other drivers to offer gas. In other words, ride your bike with the expectation of being self sufficient, not with the expectations that everyone should obligated to offer help. If I flat, it is perfectly ok that 0 out of 200 rides offers help, the thought never even enters my mind..