Disclaimer. I am not a financial advisor. Just kick off the discussion on long term strategy.
We are definitely experiencing a downtrend at the moment. Hard to say if it is long term (2 year) bear or a short term (months) correction. The current price of the altcoins may not be as cheap as you thought yet. Bitcoins remains the most stable asset out there. Just check out the price change in the past 3 crazy months between BTC and ETH. Needless to compare the other volatile coins.
As the pioneer currency, Bitcoin has gained more attentions and trust than any other coins. Some governments have accepted it as a currency, while some confirmed it as an asset. Why? Because time makes the difference. The trust and faith require enough baking time.
In the foreseeable future, BTC will be a relatively less risky asset. My strategy is to buy BTC on each $100 dip. Wait for the long term bottom to load more altcoins. Isn't it like gold vs fiat currencies? :)
I'm far from an expert, but my gut feeling says BTC will go through a correction and start to recover. I'm feeling less optimistic about ETH though, as it seems that its connection to so many altcoins is dragging it down.
I'll plan on grabbing more BTC in the dips and try to check coinmarketcap less frequently for the next few weeks.
I have faith in ETH or alike platform in the long term, 5 - 10 year. But for now, buy BTC bit by bit