I don't know about keeping all of your investment money in bitcoin for the long term, however. OP will likely still be in the black even if bitcoin were to lose half its value (if he's holding onto 2013 coins), but if I were him I'd probably diversify just a little. Normally I'd suggest the stock market, but after well over a decade of bull market craziness I'm not sure now is the best time to buy stocks.
OP, you still around? Maybe you can chime in and give us an update on any changes to your portfolio, etc.
Still all in BTC, doing fine, no headaches watching the shitty coins. Not planning to sell even if BTC price is going up right now. Might sell a small amount once in the xxx,xxx range and then hopefully will buy it back, I'm sure we will see a new ATH this year.
All in in Bitcoin is at least a strategy that still makes some sense. When I read that people go all in on some alt coin (other than Ethereum), I really get a headache. It still depends, there is a difference if you go all in on an unknown token from an ICO or Monero, but as long as you really go all in, I'd be shocked if it is not a larger well established crypto with a successful history.