Only to someone not stupid enough to already know the answer - because it's still selling in significant numbers.
OK, sloppy on my part. More accurately, "why are people still buying this?".
Exaggeration, hyperbole, and confusing a personal opinion with a law of nature... Man, you hit the trifecta there.
No exaggeration. Are you aware how many modern board games there are in existence? BoardGameGeek have just over 88,000 games in their database. I will positively assert that pretty much any of the top 1000 ranked on that site are both objectively (for reasons other posters have covered such as player elimination, rich-get-richer, king-making, duration, shortage of meaningful decision points) and for the vast majority of people who've played them subjectively (more fun) better games than Monopoly.
That said, not all of them will be suitable to sit down and play with a family who have only ever played Monopoly, hence my suggestion for just a handful that are readily available in mainstream shops and are distinctly family / non-hobbyist friendly.