Really? Is there a comparable venue available until then?
No. Kakao is building one, but don't think it will be the large.
Other option is the football stadium.. But that is not liked by Soccer fans, who complain the the turf is ruined by the concert goers etc.
But frankly, very few acts in Korea actually can pull 40000+ audience, despite what their fans believe.
Korea is not a big concert going culture
Even a top tier act will need a decent percentage of foreign fans flying in.
That's why it is rare.
Swag apart,
I don't get the deal with such large venues, where most of the audience will anyway see the act only on screens, they will be a speck on the stage,
Yes the atmosphere well be great.. but anyway m..