Are sermons (most of them anyway) a waste of time? a misuse of resources? a wrong-headed prioritization of effort?
This comment is tantamount to heresy because the ministers I know tend to mark time in terms of sermons. Service to a church is marked in terms of sermons per year. I know from experience that sermon preparation is the largest single use of time in a preaching week. To get a substitute for Sunday worship is to "get some one to preach for me." Being a good preacher is as close as the ministry has to sex appeal. (OK: some ministers do bank on sex appeal, but I'd rather not think about it.) And even this is resented. I can't count the times I've heard an exasperated preacher complain that his or her congregation wants entertainment without controversy, and certainly no room for growth or change, all protests for the goods notwithstanding.
Lay-led congregations are not only not immune to this phenomenon, but are particularly vulnerable. (Even if the term talk or program is used in lieu of sermon.) The constant battle is "who can we get ?": the net result is hundreds of otherwise underappreciated junior college professors getting a hearing on their pet topic (alien abduction? genetically modified food? Laplanders?) before a polite congregation of ten or twelve or twenty.
The idea of the every-Sunday sermon strikes me a little odd, or at least the every-Sunday original sermon. It is a waste of resources. The Elizabethan Church of England recognized this, or at least the possibility of a shortage, and appointed a book of homilies approved for reading in worship. (Homily 3: "Of the salvation of all mankind" - I wonder how it turns out?) You can find references - either articles of canon law or the actual sermons - online where this practice is continued among the Anglicans and even (in these priest-short days) Roman Catholic churches. A variation on the theme is pulpit swapping, now so badly in decline, that allowed a preacher to get two or three hearings out of a single subject. In our own fellowship, the Church of the Larger Fellowship is a common go-to resource for a sermon that can be transplanted into a setting without a regular preacher. After all, if people don't change much from week to week (or even century to century) why should we assume a soul needs to hear fifty-new never-heard-before sermons a year?
Now, if only this practice can be encouraged, both as a means of assisting the smallest churches (of whatever denomination) but also as an incentive to improve preaching among those (myself included) who could take more time to craft original sermons, or who could realistically take on a tentmaking ministry, sure in the knowledge that every Saturday night wasn't another opportunity to fail.
Now, for this idea to take hold we would need to modify our attitude toward sermons, train "re-preachers," and provide an adequate licencing mechanism. But all of these are do-able, and ought to be considered.