Again it's natural not to be in the first position always. Even the best display ad has a certain share of lost impressions related to ranking on Google. However if you're losing a percentage of impressions due to budget constraints you will likely find competitors PPC budget much more extensive than yours. Of course there are a few caveats to this story. Ranking in search results is controlled by many factors including those not related to advertising costs.
The playing field however is quite different for multi channel sellers like Amazon and smaller e commerce companies. So while Amazon can be a competitor any skilled PPC marketer knows that their smaller clients shouldn't worry about this e commerce mobile app designs service giant. Instead companies should research specialized competitors that provide the same benefits to customers but are more likely to pose a real threat.
Similarly even though a competitor's brand receives a smaller share of attention does not mean that it spends less money overall. The amount of attention your brand gets can also be affected by the number of items you have in stock and whether or not they have Global Trade Item Numbers (GTINs).