Up to roughly 30 kWp, it will always be negative (calculated over 20 years), which is why the discussion is heading towards 30 kWp.
I don't understand, why should that be the case? If you don't take some crazy rip-off offers, there should always be a profit possible.
And I still don't get what is so desirable about falling into hobby status? Do you prefer to make a loss rather than paying some of your profit as income tax?
By the way, it's not about economic viability, but about the intention to generate profit
intention. The plausible intention alone is sufficient, no matter what happens in between. I don't know anyone who buys photovoltaic out of pure green conviction knowing that they will have to pay into it every year for the next 20 years.