The points you are making sound a lot more like what you would find as political campaigning talking points for deregulation than what's actually transpiring with the German economy.
To 1): Entrepreneurship has always been a lot lower in Germany as in many other countries, as it's not seen as e.g. a capitalist virtue as in the US. The German economic model with it's widespread Mittelstand works well with few entrepeneurs and a large portion of the population working in those enterprises. Not everyone has to be a small entrepeneur and hustle all the time.
To 2): Again, basically the same as it has always been. For the typical company there isn't any more "government interference in the most minute details of running a business" than 20-30 years ago. One also has to keep in mind that (as in most countries) that as long as you are making money and act in good faith according to the spirit of the law, the regulatory bodies are a lot more bendy than one might assume according to the letter of the law.
To 5): You can very much scale your workforce up and down. Limited time contracts and long trial periods are very common. On a larger scale that is typically done via subcontractor structures. Also the typical reasons for wanting to scale down (economic non-viability) are permissible reasons for letting people go. It's also very much possible to fire people for under-performance (you just have to go through the motions of tracking their performance and comparing it to peers or documenting their non-compliance). The only stories I'm actually still hearing in the wild of people not being able to be fired is about "Beamte" (public servants).