30 years isn't that old in stadium terms. The SFS is getting up towards the same age. Last time I went to Parramatta Stadium it was fine (parking is a worry though). Strange to be complaining about capacity when you cannot half fill the ground against the neighbouring team in good weather.
The trouble every ground has is this: when a team is winning, you can't get a ground big enough. But when you are losing, no-one wants to come. This is Parra's problem now and if they are losing money this would be why. I'd suggest rather than try to get a better ground, you try to get a better football team.