He's not entirely wrong.

The degree is definitely important but mostly for the first job. It is also important as a salary benchmark since SG employers like to ask for past salary but that can change with a few promotions.

After the first job (at least a year or 2), it's really all about work experience. Nobody is gonna ask you what subjects you took in school or what honours you got after you got some relevant work experience. What they will ask you is just whether you have a degree and what projects you did in your past job to try, what systems you know how to use, whether you were promoted and how often in your past job, and try to gauge how relevant your past work experience is or how skilled you really are.

Afterall, school and work are really 2 different ball games even though HR will put more emphasis on the degree for selection when the candidates have no past work experience (i.e fresh grads or someone with little to none relevant past work experience).

In school, you are taught the method to get the answers and in exams, you are given questions that you then use those tried and proven methods you learnt to solve the problems. In fact, with sample past year exam papers that you see students practising with, the "way" to identify the problems and the suggested tried and proven methods are often already given so you have ample time to prepare beforehand.

In work, you may not even be taught a method (depends on your superior) or a method will already be given to you as company SOP (depends on your company - MNCs and ops role will have more red tape).

Oftentimes, problems are not given to you directly. You will have to identify the problem yourself and then come up with the method yourself if it is not already in company SOP. Even then, sometimes problems will be stacked on top of problems so you cannot get the perfect solution but will have to make do and adapt.

Solving problems with methods already in company SOP/given by others or solving problems that your boss give you is just gonna give you an okay career though most companies usually will still give you a promotion after a few years just to keep you staying even if you are just doing the expected. Not being able to solve problems even if you tried and tried can result in a job loss if it cost the company losses or if too frequent (depends on how forgiving your superior is). There are no method marks in work, only done or not done.

If you want the promotion then you need to identify problems in current processes where possible and/or take the risk to come up with new methods that does not completely violate company SOP or at least not illegal. If your method fail and cost company loss, your superior and you will likely have to answer for it (though some superiors may just throw you under the bus and pretend that they were not aware you were doing it that way). Anyway, this is often called "taking the initiative". This is also what some are less inclined to do because of "act blur live longer" and "can siam arrow then siam".

So, working hard in school and working hard at work is not really the same. The former requires practising the tried and proven path until you can do it easily while the latter often requires you to create a new path with risks attached if you want to be extraordinary.