Church attendance is in decline bc we've transitioned from a world where going to church is the default to one where NOT going to church is the default (at least where I live & for my peers).
This is not a new observation, but I have thoughts.
(thread, apparently)

I worry that in response, clergy and lay leadership try to make church as unobtrusive as possible. All you have to do is come to church on Sundays. Just a little church! Don't worry about everything else, come, we won't even mention the uncomfy bits, if you just come!!

Of course, this does nothing helpful. People aren't going to get out of bed in the morning just because something is unoffensive. That may work if the default is church but, well, bed is unoffensive, and bed has inertia on its side.
(I get on this soapbox a lot, I know. Sorry.)

ALL THIS TO SAY.
I wonder if when clergy discourage people from praying the Office, or we don't make Prayer Books readily available, or whatever, it's bc of this (well-meaning but, I think, mistaken) impulse to make church small, taking up as little of your life as possible.

In reality, I think the path to growth and a LT sustainability is fewer church attendees than say, the 50s, but more committed Christians.
If we're there, it's not by default. So help us make Christ a guiding power in our lives or people will give up or find a church that will.