The system is working as intended. Same as water companies getting fined for dumping **** into rivers and the sea. Much more cost effective to dump and pay the fines rather than invest in infrastructure.
Bonus! Dumping **** now completely legal for another 15 years.
They 100% want it this way, as it's often the more well-off (like Tory donors, or Tories in control of HMRC) who are committing tax fraud, who won't be investigated, never mind actually charged or prosecuted.
They're taking money away from public services which they don't even need or use, so they're not bothered, as they can buy alternatives or cover costs of problems. Mr Rich doesn't care about the NHS being screwed, he has private healthcare and could easily travel to the EU or USA to get whatever he wanted. He doesn't care about public transport, as he never uses it. Doesn't care about a pothole wrecking his wheel, as he won't even notice the £300 replacement, which would probably end up on expenses anyway. Doesn't care about the schools we all go to, his kids go to the private one, and the quality of education gets wider, so his kids have an even better chance v the rest.
Also, only the more well-off can afford the schemes which are legal, but avoid tax by diverting it abroad via a shell company in the caymans or whatever, no common man on the street can afford to do that. Someone who has £10m spare could do it though, and well worth it to save £50m in tax. See it all the time in massive companies, paying next to zero corporation tax, yet their owner has a yacht and 10 houses
Like you say about the dumping, the fines are tiny compared to what they're turning over and making in profit. If I contaminated a river with a digger bucket full of mud I'd probably get a 10k fine, which wipes out any profit for that month.
Fines and charges need to be proportional to earnings/ turnover, and an actual deterrent. If the minimum fine for tax evasion was double the tax dodged, it might help.
Interesting that loads of the richer Tories wanted out of the EU, which was bringing in stricter tax laws, specifically aimed at tax evasion. They never used this as one of their positives mind, as it's not good for 99% of people.