not so much soft, but there are a lot more entertainment options. Why stand out freezing in the rain when there are many other things you could be doing?
New stadiums are likely to take it into account, if cost isn't prohibitive. Westpac stadium were looking to get a roof but it is way too expensive. The newer Forsyth Barr stadium has a roof.
Why buy a season ticket that ties you to doing a particular thing every second weekend when you could just end up cold and miserable wishing you were doing something else.