Pressing on in our Ecclesiastes, Solomon here is talking about the vanity of toil or working all our lives, we can make all this money but we have to leave it to someone else: 

Ecc 2:19  And who knows whether he will be a wise man or a fool? Yet he will have control over all the fruit of my labor for which I have labored by acting wisely under the sun. This too is vanity.

Biblically, Solomon was right, the kids he had and the generations that came after him were terrible kings, they lead Israel into idolatry or the worship of false gods, and The One True God was angered by this and handed Israel over the Babylonians who came and completely pilfered Jerusalem and took all of the wealth that Solomon had invested into his kingdom.  

Now fast forward to 2021, most of us aren’t going to be gazzlionaires like Solomon, but the point he is making remains; what good is it to work hard only to pass your money and assets onto your heirs?  Because they might not be wise, they could be fools, like the case was with Solomon.  A lot of the wealth from rich families has ended up being squandered by their kids because they were essentially trust fund babies.  So that’s the crux of Solomon’s conundrum today, what is the use of slaving all our lives for wealth that could end up in the hands of a fool, isn’t that ultimately a waste of time?  

It should also set off a light bulb in our brains, that earthly wealth is meaningless.  Like Jesus said, don’t store up treasures that just rust and fade, instead store up treasures in Heaven, or put your trust in Christ, because those riches are eternal, and don’t break down like all this materialistic stuff we are always trying to buy.