Those leading companies already have the .com usually, they are not taking any chance.
Now, just facts, not wishful thinking:
Fact: Even Barclays or Canon have not completely migrated to their own extension. Yet they are hailed as success stories but there are better examples.
Fact: the majority of TLD applicants have not moved to their own extension. What's holding them up ?
Fact: Two dozens TLDs (corpTLDs) have already been retired:
List of retired new extensions
Plus, those that didn't make it to the delegation phase (but the applicants nonetheless lost the application fee). Example: .aquitaine. Clearly, companies are spending money for nothing. Have you noticed how the spin doctors of new extensions always report on the positive news (that is, not often and it's regurgitated stuff), but the failures are conveniently swept under the rug.
Fact: historically new extensions have never done well.
Fact: even support from industry heavyweight is no guarantee of success.
I still remember the discussions from ten years ago at NP, where they naysayers predicting the demise of .mobi were depicted as fools and ignorants. How dare we question the sanity of those big conglomerates, and the bright people leading their steering boards. As if domainers knew better than those companies, how arrogant !
How could a TLD fail when it has the backing of Google, Nokia, Microsoft and is embraced by prominent end users like BofA etc. Right ?
Plenty of projects will never see the light and die or fail on the market, It's just part of business.
What makes you think that even the most successful companies do not waste money, or take wrong bets sometimes ?
Just because you throw a lot of money at something, doesn't mean it will work.