I hope not, because I think I could answer the cabby's question. It would need to be a reasonably long journey to give the full explanation, but I could give the outline in the time it takes to get from Charing Cross to King's Cross. In fact, tell you what, I will give you the quick answer now.
I can do this, not because I am especially wise. If only! I can do it because it has all been done already. The history of western philosophy contains all the insights we need to understand the meaning of life. My view is more or less that of most other philosophers. Even the religious ones - who are in the minority - could agree with a great deal of it.
Why, then, was Russell left speechless by the taxi driver? Because the question itself is a hodgepodge. It defies a simple answer because it needs to be carefully unpacked and dissected before it even makes sense.
That's why Douglas Adams' gag about the answer to the question of life, the universe and everything being 42 is so insightful. You can't expect to get a sensible answer unless you ask a sensible question. But what the hell is "What's the meaning of life?" or "What's it all about?" supposed to mean? They may be grammatical, but so are "What's the meaning of cheese?" and "What's grass all about?" - and I defy anyone to give a serious answer