A UChicago economist and graduate student are walking across campus. The student says ... hey ... there is a hundred dollar bill on the ground! The economist scoffs and says no there isn't ... if there was one, someone must have picked it up already.
Sometimes I catch myself thinking this way. I have to remind myself that (a) markets aren't perfect, and (b) the real world has huge asymmetries in information, ideas, and perhaps willpower (by this, I mean while 100 people might think of a great idea, not all will attempt to implement it; even then, people will differ in execution).
That said, you're likely right. This trading strategy will likely lose money today :-p
In early 2000s I wrote a machine learning algorithm that beat the S&P 100 with over 1 trillion to 1 odds against it being luck. It predicted a full trading day in advance. But that was all on paper at trading firms' puny costs; unlike you I couldn't beat retail costs. It's amazing that you could do that. For that reason alone I think it's highly likely that you were a skilled monkey.
Also like you, nobody in the industry was interested in my code, even after an industry magazine watched it for 3 months and found it gave "stellar" performance. The few people I was able to discuss it with told me point blank that it was impossible to do it skillfully (efficient market theory), so they assumed it was a hoax or the algorithm was just lucky.