Problem - Companies were hiding staff by using contractors to lower their bills/tax/etc
No, I would say as far as HMRC are concerned the problem was contractors working effectively as long term permanent employees but paying a much lower tax percentage on their earning (even if the absolute takings might actually be higher) and HMRC viewing it that those people should be paying the same percentage as PAYE employees. It's the contractors themselves HMRC think are taking the ****, not the companies they're working for. To solve this, they've decided that the end clients should be telling HMRC if these people are genuinely contracting or 'disguised employees' rather than the contractors themselves, who for obvious reasons will say they're genuinely contracting whether they are or not.
The issue that raises is that because of the liabilities placed on those clients for making 'wrong' judgements, many either can't or won't deal with it properly and so are taking what they deem to be the path of least risk - get rid of contractors or tell HMRC they're all disguised employees. There is little incentive for a big business to bother spending time making truly individual judgements or reporting people as genuinely contracting (until all the contractors start leaving perhaps but my experience at the moment is that most businesses are taking a "and then go where? this applies to everyone" approach).