The bigger the opportunity, the more difficult it is to win. The nature of big deals is that there are more competitors trying to create value and differentiate themselves. There are also more relationships to manage. These factors (and many others) make big deals more difficult to win.
Larger deals generally take longer than smaller deals, unless there is a truly compelling reason to change. Large opportunities are rarer because the companies with existing partners pay a price to make a change. It costs time, energy and political capital. If there is a serious issue, however, they can change more quickly because they have more at stake.
It's more difficult than you may believe to displace an incumbent supplier, even when that supplier isn't doing nearly as well as they should. It's difficult to fire your friends, and when you've worked with people for a long time, you want to give them the benefit of the doubt. If your relationships are good, you want to keep them. This factor is often underestimated.
Your sales process is more important with larger deals. You can get away with some mistakes on smaller deals and may even be able to skip whole stages of your sales process without paying a price. But the larger the opportunity, the more closely you need to follow your sales process. Skipping stages could cause you to lose the opportunity — even if you make it to the presentation stage.
Large deals that happen based on price are usually driven by factors other than the value being created by the supplier. There are some companies that expect price concessions every year, even though the supplier's costs go up every year. It's not a sustainable model. Many companies switch based on price because it is easier than fixing what is really wrong with their businesses.
Big opportunities almost always require many people's approval, increasing the need to build consensus. No one wants to step over people and impose a decision on them that might result in their rebelling against it, digging in their heels or blowing up the deal. It's easier to get everybody on board before a decision is made. This is one reason so many opportunities die at the hands of your most dangerous competitor: the status quo.
Also, larger deals almost always come with greater risk. They generally require more assurances that the incoming partner can and will be able to execute. Big spending likely means the purchase is more strategic, even when it is a commodity. Because there is more risk, the client is likely to want more assurances and have greater concerns.
