Employment at a good-ish startup is a good investment in your skill set. Yes, ideally you will make a lot of money on an IPO or acquisition, but even if not you

Employment at a good-ish startup is a good investment in your skill set. Yes, ideally you will make a lot of money on an IPO or acquisition, but even if not you will develop expertise and broaden your network. Just throwing a few thousand at something you can only watch from afar won't get you that.