This can benefit the consumer at the expense of the supplier. The lower Walmart can lower the price, the lower Walmart can offer the product.
There is no "moving into the market", because as soon as a market consolidates around one or $very_small_number of players, cost of entry and market capture make competition impossible. So competition ends.
This is where we are now with tech. It's basically impossible for anyone new to compete with Amazon, Google, Facebook, etc. It's also where we are with established players in other sectors such as Airbus.
The only two things that can break the logjam are government action to split up monopolists, and the invention of a new market space with a viably low cost of entry.
It wasn't always that way... or, at least, not for such a large proportion of the economy. The problem is that economic models and resulting policy is still based on assumptions that, due to technological change, no longer hold. The logic is usually sound, but the assumptions are ridiculous (see, e.g., abuse of the Coase Theorem).
It's far past time to re-evaluate this perspective, but we keep running into that Upton Sinclair quote: "It is difficult to get a man to understand something, when his salary depends on his not understanding it."
Are prices high, or are prices so competitive, so low, so good for consumers, that competitors have literally been complaining about it for years?
Now, tell me again why you think prices aren't competitive?
Not market mechanism, governments protecting big biz. Without legislative protection a monopoly doesn't last long, as Standard Oil example shows.
A typical cycle of crony-capitalism is: build big biz on a new market -> lobby heavy regulatory framework and a set of monopoly rights which make entering impossible for any new competitor -> push your shills in some agency like FAA, FCC or FDA -> enjoy your unconditional domination.
> The only two things that can break the logjam are government action to split up monopolists
This factoid has failed so many times it's astonishing it keeps being repeated. A century of anti-trust failures without a single example of a decent outcome, yet people still bring this up.