Maybe the right thing for me to do would be to give it up already and switch from the cable provider to an ADSL provider. I would trade an uncertain chance of better availability for even lower upload band"width" at same or higher costs. But believe it or not, there are plenty of regions here in Germany with even worse Internet connectivity.
I would prefer a stable internet connection that gives up a bit of bandwidth throughput over a higher throughput, but constant down times. That's just me though.
Then again, if I had that much trouble I'd probably have both Internet connections and configure my edge router for load-balancing dual WAN connections. Though if the speed differences are vastly different then I'd probably configure it for a fail-over on the slowest connection so I am guaranteed connectivity at all or near all times.
Back when I was in high school and ADSL first started rolling out I had two 1.5Mbps download ADSL connections using a Nexland dual WAN router to load-balance them. Then I used one of the phone lines for a 56k connection that I had setup on the router as a fail-over for just in-case both ADSL connections dropped. I didn't have the option for a cable connection at the time or I probably would have opted for an ADSL and Cable connection combo instead. The upload on those ADSL connections were horrible though. I can't remember the exact throughput. I want to say it was around 128Kbps. Man those were the days. lol