You really don't think that matters?
We're talking market cap and that has no impact on purchasing power for a business. Its a simple equation that people like throw around, which is the share price times the number of outstanding shares.
Just because apple has a huge market cap doesn't mean they'll now get a discount for lcd display or memory modules.
Walmart gets huge discounts because of economies of scales - they buy boat loads of stuff and manufacturers give them a bigger discount because they buy soo much. Not because they have a large market capitalization.