There's a good and and a "bad" side to it Chris. You need to bring the sheer numbers into the equation to compare to Oz. In Germany alone, with a population of 80-odd million, there were 63.7 million registered vehicles beginning 2018, in an area about 1/20 of the size of Australia. The rest of Europe is no less mobile. EU population 2017 was 317million with roughly 290 million vehicles (bikes not counted!), total european pop. 511 million. All on a continent only a bit larger than Oz... the vehicle concentration is a great deal higher.
The system does help to keep many unsafe vehicles off the road, but those that know what they're doing need to wade through heaps of red tape trying to get mods approved, which can be tiring at times. Although many things have been brought into line over the past years, regulations still differ widely within the EU, each country retaining a certain amount of sovereignty.
Granted, the testing often involves quite a bit of nit-picking, but it basically ensures road-worthiness and safety requirements are fulfilled. If you could see the condition of many heavy vehicles from the Balkan states passing through at high speeds on the german Autobahn, you would have a great deal more understanding for a mandatory testing system! Bald tyres and insufficient lighting are just the tip of the proverbial iceberg, hardly working brakes, worn steering systems, broken axles and chassis components are very often found at road-side checks. It's very different having a 60-ton juggernaut without brakes ploughing through a village or a road train breaking down in the middle of nowhere on the Birdsville Track.
And don't think the bikers would be any better...

At least the responsibility sense of bikers seems to increase with their age, but you just need to look a the bikes of the kids to realise that many are playing with their lives. Their road behaviour is an entire other issue.
German T?V tests are bi-annually for privately-owned vehicles, annually for commercial personal transport, taxis/busses, etc.
piet