It is considered prudent to write a business plan and do some market research if possible before starting a business.

yes but traditionally how often was the original business plan "get acquired"? this seems like a new phenomenon?

Every company evaluates potential risks before starting.

Depending on how much of a bubble it is. When things really heat up it's sometimes more like "just send it, bro".

that's not what this is though, the "exit" is often viewed as "get rich so I don't have to do it anymore"

the exit is the business

Isn't that first step? Consider either sustainability or the exit. You start a business either to make a living or make a profit to make a living. At least in most cases.

Thus thinking of can you sustain this for reasonable period at least a few years. Or can you flip it at end should be big considerations. Unless it is just a hobby and you do not care about losing time and/or money.