The author says proxys are expensive and then proceeds to spend a shitton of money buying all that hardware.
With only 10 dongles and 10 dataplans, you can have a lot of IP addresses that are extremely hard to block. It's an one time investment, paying proxy providers is a fixed cost.
We tried to get some, but all of the ones we could get were various levels of broken or unsupported.
>>Because I could not fully trust the other customers with whom I shared the proxy bandwidth. What if I share proxy servers with criminals that do more malicious stuff than the somewhat innocent SERP scraping?