Re: No Courtesy on the water.....
Two words . . . "Backup battery". Like another post has already said too many boaters float their rigs very unprepared.
I only have a 14 foot aluminum yet I always have a second battery in my upfront locker even when I don't have my troller onboard.
I have several backup accessories: extra battery, spare gas can, spare prop, two oars, tool kit, spare plugs, several distress signaling devices (reg flares and flare gun kit), auto inflating life preservers, reg life preservers, two throw pillows, two anchors with lines, cell phone and VHF, DSC and an 8 foot antenna.
I know what your saying about courtesy on the water but you also need to look at the situation from another boaters eyes.
Most of us too many times have seen old boats pull up to the ramp, get 1/2 way into the water, go to start it (for the first time in two years) and it won't start. Then they go about trying to repair it on the ramp while others are waiting to launch. What am I supposed to do pull my spare battery out and go help them???
Or they get it started drive a 100 yards and it conks out again. Am I supposed to hang around the launch making sure everyone gets away OK too?
In your situation, if you really needed assistance that's what holding up a simple distress flag is for or just yell over to another boater if they could give you a hand? In NY we have to carry one by law. If you were that close to the launch I'm sure you don't launch a flare

. If you were 1/2 mile out I'm sure if you held up a flag or lit or shot up a flare there is "no one" reading this that wouldn't come over to help you out. But they would be pretty pissed if they rushed over and found you were out of gas or had a dead battery. Those are not emergency situations. But I'm not about to give up my spare gas can because a boater ran out of gas!
What am I supposed to do, go back to the launch myself now with my empty can and drive to a gas station, come back to my boat so I can enjoy the rest of my day on the water (what's left of it). Is that why I left at 7:00 AM to go boating that day? Sure if there were high winds, impending storm or lightning storms in the area I'd be going off the water myself anyway, so I'd gladly give up my spare tank and I'd never take any money for it either.
Same for towing. There would have to be dangerous conditions or their boat taking on water before I'd ever offer to tow.
Having a VHF we are required to have it on channel 16 and "on" while under way. We are required to offer help from a distress call and we are near by (if not required, it's at least the ethical thing to do). This is what a pon pon type radio call is, they are asking any boats in the vicinity to offer assistance.
These types of threads always start a battle of banter.
My take on helping others is that's what a $200 a year member ship in SeaTow is for. If one has an older boat or motor that would be my first investment. And only boat on bodies of water that offer towing services. Sure newer boats breakdown too but if one can afford a newer boat they can well afford a towing membership.
The best suggestion I've read when these help vs no help threads come up is that if someone is far away from their launch or port another boater should have the courtesy to pull up and at least see what their type of distress issue is. If they have others onboard, I'd offer to give them a ride back to the launch, I'd offer to radio for help. I don't tow with my rig. That's what my radio or cell phone is for. Cell phones comes in handy to call a marina if a VHF can't reach them, they can send a boat out.
We can't expect other boaters especially ones that are there for a pleasant day of fishing or only get to boat a few times a year on vacation to jump to other boaters assistance by spending the next several hours towing someone back to port especially since so many are ill prepared to be on the water in the first place, like probably 75% of the boats on the water on any given weekend IMO. How many carry a spare gas can, a radio etc, how many smaller rigs do you see with an antenna?
So in your beef above . . "shouldn't there be a general courtesy for others to offer help" my response to that is "shouldn't there be a general courtesy of boaters to come prepared for boating" if not just for the responsibility of your passengers as a captain (if anyone else was onboard) Next time just hold up a distress sign (usually says HELP in red letters) there is no one that would have not come over and at least offered to tow you in, but being you were rowing already (rowing that boat gives you great biceps

) and never asked for help (and from what you said that you came unprepared for boating with a weak battery) I too would not have offered help unless you asked for it.