How do you mean? Outside most major cities, ISPs tend to monopolize the playing field and there is great demand for cheaper or more personalized service. Having good customer relations would be a major differentiator, and it's not that hard.
Unless you meant obliteration by lobbying, lawsuits or something similar. There's little hope if your competition goes that route.
You can’t compete with large ISPs on price. They can easily undercut your price for a few years until you’re gone. And a lot of people don’t really chose their provider for ‘good customer service’, they chose fast and cheap.
If you’ve set up in an area that a big ISP suddenly sees as profit potential you’re toast.
Unless you meant obliteration by lobbying, lawsuits or something similar. There's little hope if your competition goes that route.