I've been late to a lot of things, but I wouldn't say I've missed out.
For those of you who feel bad about not buying bitcoin when it was trading for practically nothing, I wouldn't worry about it. I don't consider Bitcoin an investment because there are no measurements we can take to indicate that it is valued fairly or has any reason to rise in value over time. It was designed to be used as a legitimate decentralized currency, but people aren't using it that way, so for me personally it has no value.
People liken Bitcoin to stocks, but there's a huge difference. When you buy stock in a company, you actually have a proportional ownership stake in an enterprise that owns assets of value and presumably is able to use their assets to make money each year, which gets passed down to you as an owner in the form of dividends or growth of the company (which in turn raises the stock price). You can also very easily own an index that gives you small proportional ownership stakes in so many companies that a chunk of them can go belly up and you will still (historically) continue to make money.
I spent a couple years as a licensed investment advisor and always find the cryptocurrency discussions interesting. That doesn't mean that bitcoin won't go on to reach new highs again, but I personally wouldn't put a penny of my own money into it.