The company probably just wants to downsize, in which case offering people money to stay would be the wrong incentive. Voluntary severance packages are often offered when a company wants to get rid of staff without overt layoffs. Sometimes followed by layoffs anyway, if not enough people take the offer. The phrasing here makes it sound related to post-merger culture, but that letter is written in Corporate Newspeak, a dialect of English that is sometimes tricky to translate.