There are many different types of socialism.
Not all socialists want greater state power. Some want greater worker involvement in the management of corporations ... up to and including complete worker management. So a socialist organisation might try to help workers buy out their employers and become self-governing. One of Spain's largest corporations works this way - and they managed to operate under the Franco regime, despite that regime's opposition to the left. Actually, the Spanish worker-owners set up their own worker-managed businesses which just grew and grew. But they also buy out existing businesses. Organisations with (somewhat) similar goals exist in other countries - eg England and Australia. There are American worker-owned businesses too. They might not call themselves "socialist", but that is what they are IMHO.
Of course, turning an investor-controlled corporation into a worker-controlled corporation can be undertaken on a piecemeal, voluntary basis, or on a wholesale, involuntary basis. The problem is, any government that tries to force all corporations to become worker-controlled is also not likely to let the workers themselves have real control. This was a problem in Russia under Lenin, I believe - they turned corporations into worker co-operatives, but wouldn't give those co-operatives real self-government.
Without a strong central power pushing worker-management, however, it is hard to see how it would become the norm unless it slowly grows. If people saw it as a civil rights issue - "no work without representation" - maybe it could happen without a revolutionary coup that took control, and never let go of it. Once power grabs begin, the worst dictator will emerge - because if the current leaders are not the most ruthless available, then the more ruthless will take over.
So yes, non-authoritarian socialism is possible. But it works much more slowly and "invisibly" than the authoritarian, revolutionary kind. But it does exist.