The saying that it is easier to get to the top than to stay there is a fallacy. Once at the top, a company can use the power of its leadership position to stay there.
Al Ries & Jack Trout in Marketing Warfare
All other things equal, an army with a larger number of troops has an advantage over smaller armies. A larger vehicle has an advantage over a smaller vehicle in a collision. When several companies enter a new market, the one with the larger sales force is likely to become the leader. The larger company has the resources to outnumber smaller competitors. It can advertise more, perform more R&D, open more sales outlets, etc.
This is not to say that smaller companies do not stand a chance. Rather, smaller companies must recognize the principle of force and attempt to win the battle by means of a superior strategy, not by brute force.
Some managers may believe that they can overcome a larger competitor through superior employees. Ries and Trout maintain that while it may be possible to assemble a small group of star performers, on a larger scale the employee abilities will approach the mean.
Another argument is that a better product will overcome other weaknesses. Again, Ries and Trout disagree. Once consumers already have in their minds that a product is number one, it is extremely difficult for another product, even if superior, to take over that number one place in the consumer’s mind.
The way to win the battle is not to recruit superior employees or to develop a superior product. Rather, Ries and Trout argue that to win the battle, a firm must successfully execute a superior strategy.
Sources: quickmba.com, creativossinideas.com