Typically, the earlier in a given organization's life cycle, the less engrained the culture. However, modifying organizational assumptions at any stage of life cycle has often required more than a concerted will to change, solely based on competitive environment. History over the past 50 years provides an abundance of examples where organizational members from the "top" to the "bottom" knew of some or all of the major market challenges, but they just couldn't make the leap.
Additionally, values and assumptions "imported" from outside have seldom worked to change organizations in anything other than the superficial, over the long haul. For true change of cultural assumptions to occur, it has appeared that people have had to first experience, collectively, a "significant emotional event" (Massey, 1979, p. 18); and they have then had to collectively buy into the concept that any proposed cultural change would answer the challenges associated with that event, at deep-seated, taken-for-granted levels (Schein, 1992).
As far as convenience and unwillingness representing the motives for remaining the same; I posit that it depends on the definition of culture. Some people have defined moving from using individual computers to enterprise-wide, server-based solutions as an example of culture change. Although it can likely precipitate a culture change, does that really represent the definition? It might change day-to-day operative and political values and behaviors, but will it significantly challenge any deep-seated, taken-for granted assumptions? For example, will that type of change really challenge how people in an organization fundamentally and collectively view: (a) their relationship to their environment; (b) their understanding of the nature of reality, time, and space; or (c) their perceptions of the nature of human nature; etc. (Schein, 1984)?
Massey, M. (1979). The people puzzle: Understanding yourself and others. Reston, VA: Reston.
Schein, E. H. (1992). Organizational culture and leadership (2nd ed.). San Francisco: Jossey-Bass.
Schein, E. H. (1984). Coming to a new awareness of organizational culture. Sloan Management Review, 25(2), 3-16.