20 years ago, if you missed the "sermon" or wanted to hear it again - or give it to a friend - you could purchase a CD after the service. This usually meant standing in some kind of line and often a dollar or two.
20 years before that, if your church was on the cutting edge, you could probably get a cassette tape after the service for all the same reasons.
20 years before that, if you didn't hear what was said live, you didn't hear it.
100 years ago...
1000 years ago, if you wanted to hear anything spiritual of any kind, there were no recordings, little to no books to read (if you could read), no blogs, no magazines, no traveling speakers in the way we understand them. You had to go to some kind of "church service".
So, fast forward back to 2017. Not only can you grab the podcast the day after it was said, you can grab thousands of other podcasts, read thousands of books, thousands of blogs, thousands of articles, watch thousands of speeches... you get the idea.
The common church structure was formed thousands of years ago, when that structure was very necessary.
It has to change.