I'm generally against credentials, at least any system that would lead to loss of freedoms for hobbyists and small timers.

I guess credential requirements that only applied to specific limited contexts could work. As much as I value individual economic freedom and open competition perhaps (for example) medical, passenger jet, and certain military firmware ought to be written only by thoroughly vetted professionals with extensive track records.

But in general I think personal and corporate liability is probably the better way of going about it. I'd argue the current problems exist almost entirely due to perverse financial incentives.