It is not the pastors who are charged with maintaining sound doctrine; it is the churches. Pastors and teachers must be careful to uphold sound doctrine, of course; but ultimate responsibility is on the church as a whole. The church is "pillar and ground of the truth." I Tim. 3:15. That includes all the saints, but in particular those who are mature in the faith. The New Testament gives every indication that adult believers who have walked with the Lord for six, ten, or twelve years ought to have attained the maturity necessary for "the work of the ministry," Eph. 4:12.
A church normally should be able to count a majority of its members as mature saints equipped for the work of the ministry. Children are excluded from this group, as well as the feeble-minded. While all believers are participants in the church according to age and ministry, it is especially the mature saints who are to witness to and contend for the faith once entrusted to us, cf. Jude 3. (The faith, according to Jude 3, was "once delivered unto the saints." That is, once and for all delivered to the saints. There is no "theological development" subsequent to the original delivery of the inspired Scriptures to the saints.) Our part is to uphold this body of faith revealed in the Word.
When young men go to seminary, they may at best learn how to teach. But they cannot learn how to pastor, because pastoring is learned in the actual churches of God. Pastoring is for the elders, not the "youngers."
So do I blame these young men? Far from it. I do not expect them to be mature in the faith at such an early age. Of course there are exceptions, and famous ones, too. (Not Charles Spurgeon, however. He never attended seminary.)
Not that these young men are ungodly. Far from it. Many of these are among the best of the young believers in the churches. (However it remains demonstrably true that many seminarians are not even born again believers. These cannot preach the gospel because they have not yet believed it.)
No, it is the older generation in the churches that sends off its youngsters to seminary.
Not a few of these young men catch on to the problems with a professional pastorate as they study their Bibles and grow in Christ. Some of these men leave the professional pastorate. Many are considered failures when in reality they have simply grown to maturity in Christ and opted out of "the system." Others, coming to an understanding of the falsity of the clergy system, feel stuck. After all, this pastorate is what they were trained for. It is often difficult to change careers when faced with providing for a family.
But I don't fault the young men, I fault the churches, in particular the elders. You see, eldership was abandoned by the elders in many parts of the church during the second through fifth centuries. And since nature abhors a vacuum, the vacuum of leadership was filled by, first the Nicolaitanes of Revelation 3, and then by the "church fathers" who claimed "bishoprics" in various cities and areas.
See, there was no initial conspiracy by "the clergy." Rather, responsibility for church leadership was "subbed out" by the elders and their churches to "the clergy."
It has remained thus in most of Christendom, with notable exceptions, for upwards of nineteen centuries now. Responsibility for the demise of Biblical eldership rests with: the elders, the churches, and the parents of these seminary youth.
If the damage were confined to a small part of the church, it would be one thing. But clericalism affects every facet of church function such that believers read Romans 12 and I Corinthians 12 and 14 and don't even blink.