It is definitely a good time to buy bitcoin today because the market is increasing. Buy some bitcoins, leverage it, and with just $10 movements in the market, cash out. That will be a good amount of money considering that you only spent a couple of minutes/hours doing it. The price of bitcoin is increasing right now and you can take advantage of that by doing a short trade. Unfortunately, if you buy now and you are looking for a long term investment in bitcoin, I think you shouldn't do it yet as well as in altcoins. You don't know which coins are going to die because of this rise in bitcoins price but I do see a lot of altcoins going down so hard.
For a long term investment, you should just hold your money. Buying while bitcoin is at its peak price can be a mistake. Just think about the people that bought bitcoins for $1200 in 2013 and the price went downhill to $200 in 2015. They had to wait for 4 years just to get back on track and that's not the kind of commitment you are willing to make, then don't buy just yet. Let the water become a little less raging before you invest.
I disagree on your long-term investment views. The example you are giving is one I usually give as well to tell people not to be overexcited and be prepared if bear market comes and stays for a while.
However, what I think is that if you are a long-term investor is because you have researched what bitcoin is and you firmly believe in its long-term potential. So, what you should do in that case in not to try to time the market. The fact that we reached an ATH doesn’t mean that this will keep going up without falling but it doesn’t mean that we are going to have a bear market like the one you mentioned either. Actually, a strategy in buying stocks is only to buy them when they reach ATHs.
Besides, most people don’t have a huge amount of money that they can invest at once. What they do is they save money to invest and buy and in this case it would be silly to try to time the market as well.
