Since the government started taxing dividends at significant rates on top of the corporation tax already paid any small owner-run businesses that pay out via salary+dividend arrangements are close to the same total tax level as an employee pays in income tax and NI. You're actually quite a bit worse off financially now if you equate gross revenue for the business with salary for an employee because the business has to cover all its own costs in terms of paid time off, pension contributions and so on. And of course you have none of the job security and other protections that employees have under our system.
The only ones who really win big under the current system seem to be the employers of disguised employees because they can dodge employer NI contributions if they pay via a Ltd company outside IR35. But they solved the problem of getting hit with employer NI under IR35 by forcing contractors to work through umbrella companies and then pay all of the costs for both employee and employer themselves. And since that has widely been done inappropriately through blanket policies and lazy status determinations since the rules that are now to be repealed were introduced the one really big tax anomaly in the whole system is the legitimate contractors (and other independents like freelancers) who have been hit with a far higher tax bill than anyone else.