Why do some sociologists think that capitalism and socialism were converging?

Beginning in the 1950s, both socialism (in the East) and capitalism (in the West) began to rely on forms of economic planning within firms or within the economy as a necessary measure to coordinate activities in large industries. Industries grew larger because of increasing returns to scale, and within capitalism, there was a growing movement for more workplace autonomy and self-management within companies, although this was very limited.

It was also envisioned by some notable economists and sociologists like John Kenneth Galbraith and Joseph Schumpeter that management, planning and organization were becoming increasingly specialized roles that would have to be fulfilled by trained, technical experts in their respective fields, eroding the case for small-scale entrepreneurial capitalism -and- democratic socialism.