the real question is, does Wal*Mart wield enough power to exercise unelected, unaccountable centralised planning authority over the marketplace, i.e. do Walmart elite planners privately make decisions which control the supply, price and quality of goods rather than allowing customer choices and the "free market" to work?  and I think the answer is very plainly Yes, whether we call this monopoly or monopsony or oligarchy or just Bullying:  the issue is control and power, or the centralisation of control and power into the hands of a small unaccountable elite.

the same bullying will almost certainly manifest in any business enterprise allowed to grow beyond a certain size.  it will by sheer market share exercise "undue" influence over the marketplace, restricting consumer choice and meddling in the affairs of smaller businesses.  another good example would be the 2 giants Borders and B and N, who in the US publishing market are no longer just book sellers, but are invited by some publishers to preview and judge the proposed list for the coming year;  promising authors can be rejected, and house editors' judgment overturned, by the marketing departments of these two retail bullies.

a side effect of this bullying behaviour is that innovation will be stifled as the lumbering behemoth, driven by its simplistic profit motive [the lowewt common denominator that holds together a huge corporate monoculture organisation where personal quirks and passions are verboten] and beholden to ever-larger groups of investors and interests, will be loath to take risks.  it will use its undue influence to stifle competing products and businesses;  and as with US publishing, TV, and movies, the largest outfits will stick to recycling the same old formula that succeeded last year and the year before that.  Gargantua will be most unwilling to risk anything on new talent or unusual ideas, and unable to change its organisational direction any faster than a BCC.  the cultural stodginess and tedium of the old Soviet Union was imho partly ideological and partly an inevitable byproduct of gigantism and bureaucratic, centralised management:  the Peter Principle works itself out most fully in large organisations.

I'll propose the following: when any commercial enterprise reaches a certain critical threshold of size and power, it should either be broken up into smaller competing firms or nationalised.  if it is to remain a giant, it will exercise government-like power over lives and buying decisions, and should therefore be broken to the bridle of the democratic process -- with full transparency, citizen oversight, elected officials, and strictly limited profit margins.  below a certain size, a business should be allowed to pursue independent policies, take risks, grab for high rates of return at high risk, and frolic in the free marketplace of ideas and goods with its competitors.

good candidates for nationalisation and public utility status:  centralised energy, public transport, telecomms infrastructure, water delivery and treatment, policing, firefighting, security.  bad candidates for nationalisation:  restaurants, theatre, the arts, farming, publishing and newspapers.

any takers?  where would the size threshold be?  what else aside from size distinguishes good vs poor candidates for nationalisation?

The difference between theory and practise in practise ...