15k is good enough for an All Blacks test match in Christchurch, why wouldn't it be enough here? And if we lose the Sevens, is it really that much of a big deal? Nobody bothers to show up anymore, it might actually do more good for the city than harm if we lost it.
I do concede that cricket will suffer. If only we had one of the best cricket grounds in the world just a 10 minute drive away...
Christchurch is not getting the decent rugby tests and that wont change until they build their new facility. Wait until the British and Irish Lions come in 2017. The best that Chch will get is a tour match not a test match. The three tests will be in Dunedin, Wellington and Auckland. The three with the biggest capacities. Economic fact of life for the rugby people when they know that with the British tour groups that come means they could sell out any venue in NZ twice over.
I think you might be onto something there. Cricket got their wetdream of building an oval in Hagley Park for the ICC World Cup 2015, despite the fact the founding fathers set aside the Hagley Park as grounds for public use, not for a privatised sport. Could be that the ChCh stadium will be pushed through (despite public opposition to date due to other public priorities) in time for the Lions Tour if one follows your good logic.