Depends
I have known contractors who have worked exclusively for the same company for a very long time (20 years in one case), and they really should be classed as employees for tax purposes.
But probably very few of them became contractors with the express aim of finding a permanent job then fiddling the tax system. Most likely they got in with a company, had their contract extended, didn't see any reason to go looking elsewhere, and time drifted by.
That is the problem - exactly when does a genuine contractor become a de facto employee. HMRC have pushed the limit back a bit to far.
This is especially true when other, better paid, sectors are doing exactly the same thing, arguably in a premeditated way, and getting away scot free.