A bit over a year ago, ETH's market cap was 83% of BTC's. Today it is below 20%. What happened?

It can almost be hard to believe today, but there was a time where people were adamant that the market cap of ETH would take over BTC. This thought seems ridiculous to many today, but at some points, one can understand why people would think so:

Image courtesy of https://www.flippening.watch/

The question now is whether ETH will keep on weakening compared to BTC or whether it will jump again? In December, ETH went from 16% to 63% so it could be incredible to catch such a jump again. Even for those more interested in BTC or other coins longterm.

Arguments that the crisis of ETH is temporary:
ETH itself is a good project based on a serious group of developers. The main issue is that a lot of ICOs of poorer coins were done it ETH. As the market is generally going down, these groups have to sell out ETH to guarantee a continued operation - even if ETH itself should be valuable long-term.

While the ETH-BTC ratio has been briefly down at 0.027 a few days ago it is currently at 0.033 (more than 20% up in a few days). Not so far ago, the ratio was above 0.08 so there is still plenty of potential movement upwards.

Arguments that the crisis of ETH is permanent:
While ETH did show a lot of promises with decentralized apps - the reality has been disappointing. The most used dapp has likely been CryptoKitties - a (silly) game. CryptoKitties brought the network to its knees as the network could not handle the transactions needed. There is development to make the network more efficient but those may be years away from successful implementations.

A sceptic could thus ask whether

1. Ethereum has had its shot at being a "world computer" but was shown too weak? Other projects could take over in the meantime - leaving ETH in the dust.

2. Do we even need dapps in the first place currently? If the best we can do is CryptoKitties, then maybe we should just stay with the tried and tested BTC?

On the first of January 2017, the market cap of ETH was less than 4% of BTC and there are no natural laws preventing us from going lower still.

How do we act on this?
Personally, I see some sense on both sides of the arguments. ETH could rise a lot from here, but I would be afraid to hold on it while going on a 5 years hibernation. I am holding most BTC by far, but still holding roughly 12% in ETH. If we see ETH going lower, still, I may consider to risk it and pick up some more.

What are your thoughts? I would love to hear them.