A rethink is overdue
The fundamental issue is that governments around the world haven't been able to keep pace with technology. The days of buying what you need at the corner store, while working for a locale mployer are gone, and they aren't coming back (Sorry Greens).
Now I can buy training from America, drink wine from Australia while following the course on a laptop made in China, eat cheese from France between gobfulls of vino, and dump the lot in the bog the following morning while wiping my ass with toilet paper from Poland. Where exactly does the UK add any taxable value? It doesn't. While cases like Amazon & Google may look a little like tax abuse, they are following the law as written.
Tax revenues will fall over time as mobility of effort and product increase. I might live in the UK, but if I remote into a server in America and work there for a company based out of Bermuda, where is the income earned? Tax lawyers might say the UK, but what if I stuff in an intermediary between me and the Bermudan entity, one based in say BVI. The BVI company recharges me to the Bermudan enterprise for £550/day while paying me minimum wage. Lots of countries will claim the value is added in their location and so that is where tax becomes due (intelligence in the UK, margin in BVI, computation in USA, value in Bermuda). They can't all be right.
Lets refocus on sales for a moment. I buy a Kindle from Sarl, delivered to the UK. I then fly on holiday to Spain and buy a book published by a German through the Kindle via Amazon sarl. Who is entitled to tax what and why? Now consider that I instead fly to Thailand and buy the book there. Does the EU forgo the taxes willingly, and who is actually remitting the VAT/GST/WTF to Thailand?
Competition for those tax revenues will increase, as will the costs of collecting them (enforcement), and that means the cost of government has to decrease. Either governments get used to doing what they do now far more efficiently, or they have to determine which services they cut. It would be better for society as a whole if they start this now while things are just warming up, because 20 years from now this level of avoidance will all seem like a drop in the ocean.