One problem I've seen people encounter when hiring "solid entrepreneurs" is that the "entrepreneur" may be very used to doing everything themselves, and to making all the decisions. Sometimes, this makes it very hard for them to cooperate with a larger team, with priorities that are decided by negotiation between different parts of the team.
Obviously not every entrepreneur has these weaknesses as an employee, but some do.
Or maybe they are glad to leave marketing behind and focus strictly on their core competency. But in any case, yes an entrepreneur might not do well within a larger team, but that's a judgement call for the acquirer to make. Certainly seems like no more risk than a great interviewee becoming dead weight on payroll.
Obviously not every entrepreneur has these weaknesses as an employee, but some do.