There are many trading bots. But none of them will be performing consistently. That is the reason all the developers come forward to sell them because instead of using those bots for own trading, selling them would be more profitable.
Yes, another reason might be they are not sure about how their bot will perform on different market situation. Similarly mining ASIC companies are selling their latest inventions to make profits instead of using them for their own mining. If the use them for own mining, when mining difficulty rising up due to other competitors are developing similar capability ASIC, they cannot make profits. So, it would be highly profitable when they sell them instead of using.
It would be highly foolishness when we are expecting someone come forward for our wellness. When they are selling out their responsibility and business find one good end rather than struggling with them continuously.