If you don't have the budget like IBM, Microsoft, etc. to schmooze with those with purchasing power, you can do what Atlassian does, which is sell from the bottom up. The idea is to make the product cheap enough that individuals/departments will not have to go up the purchasing chain to pay for it. Hence their use any of our products for $10 for up to x number of users.

If your product is able to solve a problem of theirs, you'll have evangelist within the company and they'll spread the word within the company. And eventually their product will reach somebody with purchasing power.

It's about who you know more than how good you are.

This. Certain disreputable companies in my sector are recruiting staff from competitors just for their contact list.

I'm sure this happens in all industries and sectors..

The takeaway I feel here is that if you are considering working at an enterprise-focused company (or especially startup), try to get a feeling for how well connected the leadership is, because that will make or break a lot of deals.

Not all industries and sectors although it's more common than not. I've done a bit in most industries.

The most successful companies I've worked for have no contacts and sell directly. The most politics-filled and most likely to fail enterprise products have always been sold via the "old boys networks".