Bob K said:
Because the reality is that, while soaring
is a wonderful and fascinating and engrossing activity, it is not for
everyone. Maybe one in person in what, 300? 500? maybe 1000? takes a
20 minute ride and sticks with it through to the license.

From what I have seen of this sport it is mostly made up of airplane
pilots who have
also taken up soaring. At least in my club it is. I would guess it is
the same elsewhere in the US.
It seems this makes it an easy license transition to get into a
glider.
Some of you have talked about what trainers were used in the 50's and
60's. This is largely irrelevant
now because in ~1975 flex wing hang gliding was born. And later,
paragliding.
Now anyone who has that (cursed) soaring gene can afford to soar, buy
a new glider and a complete vario/altimeter/ IGC logger for a few
thousand $ and
fly XC 100 to 300 km. on good days. And it is every bit as thrilling
as going 500 km in a sailplane. Without the towing fees.
The only things driving these soaring aficionados to sailplanes is
that some are getting too old to lug gliders
around AND they now have a little more cash.

What I am trying to point out is that we are not realistically looking
at the whole picture when thinking about how to grow sailplane
activity.
It is a lot harder than it was in the 60s when that was the only game
in town for motorless flight.
My prediction is that sailplane soaring will continue to be a
shrinking sport and there is nothing you can do about it unless
you can a). ban other forms of gliding and b.) greatly reduce the
cost.
A third item might be to try and get today's youth away from their
glowing screens long enough to participate in real-world activities.
HG and PG numbers are declining as well!