Not always. The Whigs didn't disintegrate due to losing elections but because of internal conflict and factionalism over the slavery issue. Some of that is going on here too with both parties. There are large factions in both parties who are currently driving change and winning/losing past elections hasn't really played a major factor. Look at the data, the GOP won the last election cycle. The Dems won the previous POTUS cycle.
The Dems have probably as many pissed off constituents clamoring for change as the GOP has and they lost the last election cycle. Rather shoots down your theory. Bernie has tapped into a well spring of pissed of voters just like Trump has.
So what's the difference? Why is the GOP disintegrating and the Dems are business as usual? I would argue there is a greater degree of internal conflict and factionalism within the GOP.