Your comment is, unfortunately, propaganda and little more.
Businesses are not paying out "lavish" rates to attract talent, and certainly will not pay more than they need to for it, just for the sake of paying more. To get to the equivalent of a permanent salary, you have to throw in: employee benefits (sick pay, pension, holiday pay, any other perks the employer offers) plus the fact that it is much harder to be made redundant plus severance pay. You can't just pick any random rate you like, either, e.g. £800, because the relevant comparison point is how much it'd cost to source a permanent employee to do that work. Sometimes, the hiring firm cannot do so at all, e.g. where the expertise required is niche. You also need to deduct the costs of hiring an accountant, maintaining records and the cost of carrying the required insurances. Because the client does not have to go through an expensive hiring and firing process, they can afford to pass a little more onto the contractor in their rate. This is how business works. Time you grew up and acknowledged it.
Onto the matter of taxes. Contractors pay around the same amount as a permie, particularly now that the dividend tax has been introduced, which more or less covers the same amount as employee's NICs. What it does not cover is the EMPLOYER'S NICs. However, why should the contractor bear this cost? It is the client which is not paying this through engaging the freelancer. They will very rarely pass on the savings from this to the contractor, and arguably due to the nature of the relationship, it is right that they benefit from these savings. Yet, if the government did wish to effectively redress this imbalance, the correct approach would be to apply an off payroll tax to the engager, to the tune of 5%, and NOT the contractor.
Bear in mind that your comment is also a caricature - many freelancers are individuals on pretty average if not low rates, below £300/day (as I discussed above, this is significantly reduced once all the costs above are factored in plus taxation comes out of it.) This is particularly the case in the NHS, which is now struggling for resource and utilising the off payroll reforms, with the help of third parties, to wrongly place workers INSIDE IR35, when no fair assessment of this has been made on an individualised basis, as is required by the law (this is known as blanket assessments.) The NHS and other public bodies are doing so to benefit from tax avoidance schemes,saving them on VAT.
This will be repeated in any extension of the off payroll reforms to the private sector. The problem is, freelancers on low or average rates, are being stuck with the deemed "employer's" NI tax bill, seeing their rates reduced as much as 30%, and then tempted to sign up to avoidance schemes which are sold on very misleading terms, and are easy to use to fool those who are not experts in tax law... HMRC will then recoup these taxes from these already maligned workers years down the line and heap penalties on top. How is this fair? There is currently no direct appeals process for the off payroll reforms in the public sector that a worker unfairly deemed INSIDE can avail themselves of.
Please educate yourself before spreading virtue signalling, feel good nonsense. Ultimately, not only should these reforms NOT be extended to the private sector, but they should be rolled back in the public sector, IR35 scrapped, and the Taylor Review taken into account to bring in something more workable, like an off payroll tax on engagers in some limited scenarios. HMRC's conduct on this matter is also ripe for a review.
Articles supporting these points below:
https://www.contractoruk.com/news/0013633nhs_vat_dodge_could_cost_more_ir35_reforms_save.html
https://www.contractorcalculator.co.uk/payroll_ir35_perceived_tax_avoided_hirers_hmrc_543210_news.aspx
Further, a piece debunking HMRC's claims:
https://www.contractorcalculator.co.uk/payroll_ir35_factsheet_hmrc_541410_news.aspx
https://www.contractorcalculator.co.uk/docs/20180808-CESTNotFitForPurpose-ContractorCalculatorWhitepaper.pdf
https://www.contractorcalculator.co.uk/cest_exposed_hopelessly_unreliable_hmrcs_foi_543610_news.aspx