it's only when its market value is at or below the value of its assets and expected revenues that it suddenly becomes something everyone could be interested in buying out
That is only true if you buy the company as a simple monetary investment: buy, break it up, draw divident, or sell it when you find someone willing to pay its actual value. But if you are buying because the company fits well with whatever your own business is, then its value may be a lot more than the value of its assets on the open market. For instance, the company's patent on rounded corners may be worth squat to anyone... except to the company who can use it to lock out a competitor (or prevent from being locked out themselves). And that's actually where the GPs argument falls flat: buyers who are not interested in Twitter's ability to sell ads but in other things (patents, talent, research, user data, or the users themselves) are not likely to care overly much about reduced ad revenue or a damaged brand name, and will be happy to see the share price plummet.
they see STEM as the future, the best way out of poverty and for modernising their country. OTOH, look at the erosion of science courses in many western countries
Just look at the people studying science at those western universities. These days, a fair number of them are from Asia or the Middle East. And maybe it's a cultural thing, science isn't just unpopular here or perceived as "too hard", it's actually looked down on a little. I can remember when being an engineer in any field got you social status, and putting that title next to your name meant something. These days? Just listen to every single movie dad talking to their disappointing child: "you could have been a doctor or a lawyer".
Hard work has almost no correlation to success, I've found. The ability to convince people you work hard is more important than actually working hard.
My own experience is somewhat limited, mostly working in office environments and people having a degree, but I have largely found that most employees treat their work seriously, will put in the extra effort when needed, and are generally keen to do a decent job. Of course they will also goof off at times, take personal days, or sneak out early to run a personal errand. Here is where things start to be about appearances: most people do not really know what their colleagues are actually doing, but they can see them around the office, when they get in and when they leave. You get no points for actual hard work, or working faster or more accurate than anyone else. You get points for showing up early and leaving late, i.e. for keeping your seat warm. And if you work irregular hours, people will remember you coming in late and leaving early, and forget you working late or showing up before the crack of dawn.
This mostly affects your general reputation around the office, though. Your manager who has a say in your promotion (or in renewing your contract) should know what you are actually up to, and often they do. If you consistently deliver good work on time, i.e. work hard, it does pay off. Just don't forget to demand (not ask, demand) that work to be recognized when you deserve it. Success comes from being good at negotiation your next job... being known as a hard and competent worker doesn't hurt your position in that negotiation, but it's only a small part of the equation.
When I left you, I was but the pupil. Now, I am the master. - Darth Vader