There is another factoid operating upon the bubble issue.
Bitcoin has a finite total coin limit: 21000000.
This fact is a 'prevailing wind' driving BTC pricing in exactly one direction.
Ethereum, on the other hand,
simply spews out new coins at the whim of whoever,
making ethereum extremely susceptible to bubble pressures.
As explained on https://archive.fo/hhouj ,
ethereum inflation rate is not merely unpredictable.
The price can implode when the supply exceeds demand.