Once a corporation can influence the government, it can entice the government into giving it perks/contracts while reducing its share of the tax burden. In some cases, these corporations have even used their power over politicians to facilitate international deals that would benefit their interests—this has allowed them to turn some countries into their proxies for negotiating international deals (ex. TPP)
For example: When Haitian politicians attempted to increase the minimum wage to $5 a day, various textile corporations used the US state department as a proxy in order to fight back.