Very constructive criticism, which should lead to a revision of the methodology presented in the course.
Constructive observation, but this approach would be impractical because it would require a lot more investment in research and would therefore delay the all-important product development process.
Completely incorrect. TAM estimates should only be done after the first revenue is booked. Without actual revenue any TAM estimate is unreliable, not useful and therefore not worth the time investment.
The size of the market is far from being the most important criterion in the decision to select a particular beachhead market.