It's just another way to maximize revenue. I recently got a Visual Studio Ultimate with MSDN subscription though my company. If I go to http://msdn.microsoft.com/en-us/subscriptions/buy.aspx it looks like that's $11,899.00 yet when I looked on our internal site it was ~20% of that of that price. If the actual price is really 20% of that why even list the price? Well most of these sites are designed to sell to billion dollar companies and only a tiny fraction of the people visiting that site have the authority to purchase their product. Ideally, your contact info has value to them, and they trade pricing info for it.
But as an upside, you can often start using the software before the sales process finishes. Which is a fantastic end run around the 'approved' > 'negotiated' > 'purchased' process which can take forever at large companies.
The problem is that not everyone works at a startup, armed with a credit card.
If you sell to the Fortune 500 or government, a procurement officer does the purchase. The procurement guy's purpose in life is to extract discounts. With government, it's even worse, as you have GSA and State contracts with published price lists.
There's also legal complications. If a vendor gives a discount to one government entity, all government entities qualify for that price by law.
But as an upside, you can often start using the software before the sales process finishes. Which is a fantastic end run around the 'approved' > 'negotiated' > 'purchased' process which can take forever at large companies.