In the video, what did Homer incorrectly assume about the elasticity of demand for elephant rides?

How do the other determinants of demand from the textbook, particularly budget, affect the elasticity of demand for vehicles and medicications?

Could some people have high preferences for a particular type of vehicle (truck, SUV, etc.) or even a specific make and/or model of vehicle?

Could people adjust their dosage of medications (against advice of doctors) when prices go up to spread out the amount they have? Could some people choose to stop buying it at some point?