If you exit as a $10 billion unicorn, does it matter if the wheels fall off immediately after?
It only matters if you have any morality since selling a company to investors for $10 billion when you know the wheels are about to fall off is not exactly the right thing to do.
Assuming a voluntary transaction, it is incumbent upon the investors to perform any due diligence they feel they are entitled to.
As long as everything is fully disclosed, an investor may purchase without recourse.
For example, M. Cuban achieved a $1 billion valuation of a company on $3.1 million in revenue and $2.7 million in net losses. This was transformed into a $5.7 billion exit months later. Yahoo's market cap was then chopped down by about 80% over the next few years.
As long as you don't lie or omit required information, you're not required to point out that a particular growth metric is slowing down, and can point to a different one.
(and as one of the other comments has pointed out, quite often the acquirer will shut down the acquired)