Actually that comment itself is a sweeping statement. On what basis are you saying that SIM grads are more street smart and "entrepreneurial" as compared to the local grads?

At least I can say that most local grads are definitely smarter than SIM grads. Reason as you've stated: Able to score well at exams. You definitely need to be smart enough to process what you've studied to apply them during the exam to score well. You may argue that some people are late bloomers, and hence did not score well for "A" levels or during their poly stints. Then those ain't smart enough. Conversely, you would say people who skipped grades and received their tertiary education at a young age (e.g. graduate at age 16) as geniuses wouldn't you?

Scoring well for exams isn't as easy as what people make it up to be. Those who say its easy are either really intelligent, bull-shitting, or just plain lucky during exams.

I'll give an analogy to summarize. Imagine you're playing an RPG and your character is a sorceress. Would you wish that you have:

1) high mana but low number of spells for now (i.e. local grad with intelligence, but lack of experience to put knowledge to use, aka street smart); or
2) high number of spells but low mana (i.e. SIM grad that's street smart, but not so "book smart").

Mind, you can still learn new spells along the way, but the inherent mana difference between the two options at the start will always be there even if mana level increases as you level up.