Yeah but cracking down on a few million people avoiding a few tens of thousands of tax is hardly a massive amount is it.
It's quite a small, easy change to make to bring in a large amount of money compared to an ongoing OECD project to re-write the International Tax rules to go after the companies previously referred to.
In my mind, the laws for the international companies have always been there. HMRC was just too lenient on some companies who abused the rules.
Unfortunately the media don't help with understanding that you don't pay tax on revenue, you pay it on profits. The allocation of expenses and therefore profits are the things that determine the profits.
For Amazon, as an example, they had all sales going through a Luxemborg or Irish company (if I remember rightly). The UK was then just a service provider. The new rules prevent this from happening so they need to change. However, the UK still does very little to actually contribute to Amazon's overall profit it makes on the products it sells you. Most of the work is on its software/website which automatically calculates the pricing, manages supply chain, etc.
Putting a product in a cardboard box isn't exactly revolutionary so the UK shouldn't be remunerated very highly. That's the problem, people see £5bn of sales to UK customers and think they should pay tax on 100% of the profit Amazon generate on that sale in the UK, which isn't reflective of the huge value adding development team they have in the US for example. It's all about determining how much value each country contributes to the whole Amazon process.