Sola Scriptura is nothing more that a pair of words indicating a complex set of ideas centered around the concept of epistemology: how do we come to know what we know? Most people seem to understand, even if tacitly, that there are two main sources of knowledge: rational and empirical. Theists would add one more: divine revelation. Paul the Apostle lists 5 sources of divine knowledge, which the Spirit of God has granted to Christ to give to his church. Apostles, prophets, evangelists, teachers, and preachers.
The foundation of our knowledge of God's will are the Apostles and prophets, and their oracles and messages are found in the holy scriptures. The Doctrine of Sola Scriptura, as I understand it, not only posits that the apostles and prophets are the ONLY reliable source of divine revelation, but that their writings are accessible to anyone who can read.
The RCC, on the other hand, has placed itself between the scriptures and the people, teaching the people that the scriptures are too difficult to understand, and that one must come to the RCC for the authorized interpretation.
Your view about protestants is based on the errors of sinners, who like the RCC wanted to be the sole source of divine revelation. "New boss same as the old boss." I'll grant you that. Nonetheless, the doctrine of Sola Scriptura itself is not the cause or source of empire building. Those who truly practice Sola Scriptura are not bound to any religious authority whatsoever. Not every protestant who ostensibly believes in the doctrine of Sola Scriptura actually practices it. Many protestants affirm denominational doctrines, just as many Catholics affirm Catholic doctrines. But those who practice Sola Scriptura are independent thinkers who study the Bible by themselves or in groups or under the guidance of Bible teachers but always taking responsibility for their own beliefs. An independent Bible student would never say, "my teacher says this", or "my denomination says this." Those who practice Sola Scriptura do business with what they learn from Jesus and his apostles and own the truth for themselves because they have done the hard work required to gain such knowledge. And ultimately those whom God is saving has poured out his spirit into their hearts, so that some people gain divine knowledge in a direct way.