If you paid half that premium to the members of the team, you'd be much more likely to get them all to come over as a bloc than you are by purchasing the company. And you'd have the other half left over for hookers and blow.
Unless you value the goodwill or IP of the target company, it makes no sense to buy out the original investors of the target company.
You consider the position of the hirers, but you fail to consider the position of the investors and the founders. Why would they be incentivized to accept this offer?
First: why would the investors of a company allow the team to be bought out from under them? A good investor will align the incentives so that the founders are incentivized to exit at the same time as the investor.
Second: why would a founder of a successful company accept a hiring deal? Most founders (heck, most developers) turn down several job offers before the second cup of coffee. And even if the $ paid to founders for acquisition vs pure hire is identical, there is an important psychological distinction between being bought and being hired that affects both the negotiations and the status and authority of the "employee" at the acquiring company and thus their wellbeing and autonomy. These factors matter.
If you want the employees, and not the assets of the company, who cares about the investors and founders? They're not parties to the transaction. How could they stop the team from being "bought out from under them?"
Unless you value the goodwill or IP of the target company, it makes no sense to buy out the original investors of the target company.