Sola Scriptura is basically the response given when others have tried to put extra-biblical things above what the bible says about matters. The Bible is THE Word of God and there is no human document written by anyone else that is equal or supercedes it. No tradition of man supercedes anything in Scripture either.
And as far as a cult of personality is concerned, I would suggest that the Roman church has its own cults of personality and it’s probably not a line of argument you want to use to make a point other than one that ends in “remove the beam from your own eye, then help your brother remove the splinter in theirs”.
Fact is every denomination has issues. Some are actively trying to fight apostacy while others are embracing it and calling it “good”.
I was actually defending Sola Scriptura by showing it does not mean Bible Only but that it mean Bible is the primary authority and all other teachings must derive from it. This means that you have articles of faith, confessions, creeds, and doctrines which take their authority from the Bible alone. It is the Bible that gives them their weight. Each person in such denominations is not free to teach doctrine which is contrary to these. It is not a case of everyone is their own Pope.
By cult of personality I did not mean just any Protestant pastor. Think prosperity gospel preachers and such. You know the sort they do not represent most Protestant denominatons. Again it was not a remark against the godly ministers and reverends in Protestant churches but about hucksters who use the guise religion to prey on the gullible.
Such is not likely to happen if the congregation can point to established church teaching and say “wait that is not what we believe.”
Whether Catholic or Protestant established teaching is an important tool in battling heresy. If a Reformed preacher was to start teaching a belief in infused righteousness one can point to the confessions (I hope that is the right document)and say he is in error. But without such established doctrine and by saying only the Bible is to be used you can have varying interpretations on that subject and no clear teaching will emerge. That is Solo Scriptura.
Every heretical belief has its orgins in somebody deciding they alone really understood what Scripture meant. The purpose of articles of faith and the like is to make clear what a church believes and holds to be true.