"Allowing audits to go back for only one year is ridiculous." The provision is to limit the time the IRS has to conduct an audit, not limiting the selection period which is 3 years unless the IRS can prove fraud. (which by the way has been defined downward to in some cases cause very small errors to now qualify as fraud.)
"companies that will deal with the IRS for you?" - You deal with the IRS..... The process is extremely complex, has unrealistic time constraints on the taxpayer that the IRS makes even tighter by their holding results till the last minute. There is a maize of regulation and process that takes years to learn in order to even file an appeal, making bad assessments stand due to an inability of the taxpayer to follow the complex procedure to file an appeal (all of which is regulation and NOT legislation).
"who got bills of $ 100,000 settled for just $10,000? That seem fair to you?" YES
"while business owners search out ways to cheat." Don't know where you got your information, but it is completely false. I am an accountant and work for several companies. I have only had one client that was under reporting income, and as soon as I found that out I "dismissed" that client when they chose to not correct past returns, which is what almost every accountant I know would do (and are required to do based on ethics). There are some industries where under reporting is possible, but most of the time it's not the business owner but an employee or employees that are skimming cash (mostly in cash businesses like bars) due to poor internal controls over the sales process. But not very many. Most businesses operate on such a tight margin that they can't "skim" or they won't be able to pay their bills. And the highly profitable business owners don't under report because the risk is too high. They could loose the business they have built up over years if they under report.
Let's all just recognize what the real problems are. 1) The IRS has become more abusive that they were in the past (and that's tough to do, because they have always been abusive of the taxpayers). 2) The tax asking has grown to a level that is simply not sustainable at the taxpayer level. 3) Business owners are treated differently than their employees when tax time comes. (As a minor example, a business owner can provide health care benefits for employees that are not taxable to the employee, and are deductible to the business, but not for themselves.)