I have experienced first had a “failed” acquisition of a start-up by a large medical device manufacturer. It was clear in this failure there simply was no integration lead or team, or if there was, they were distracted with larger problems in the business.
Without strategic direction and a clear way the start-up would fit into the existing business, the start-up R&D team was pulled into a huge number of projects that did not appear to have strategic value. In the space of two years, there was therefore no appreciable change in the start-ups core product and its capabilities were overtaken in the market by competitors. The core product was too hard to sell and hence the medical device company collapsed the start-ups sales team.