Why does everyone keep thinking we would be able to recognise a higher intelligence?

It seems relatively safe to assume that the higher intelligence will deduce that the biggest threat would be let the idiots know that it is smarter than them. By the time we figure it out, it will already be too late.

Whatever test you come up for sentience, there will be a % of the human population that fails it.

The problem with the question is that there is not just 1 type of platform. There are innumerable platform definitions, whether it be a 2D or 3D gaming platform, a windowing environment, a massively parallel cluster computing platform, etc. At some point, someone decides to extend the platform definition to account for a new capability. Reaching consensus either takes time or results in forks.

In capitalism, money == power, people can get enough money, but there is no limit to the human desire to acquire power.