While I wasn't a fan of VFL Park, what actually killed it off was political influence. The MCC Trust feared the MCG losing the Grand Final to Waverley and so used its influence within state government to block moves to expand capacity of VFL Park as well as block moves to build a railway line out to Waverley and Rowville.
Originally, the plans for VFL Park were to eventually expand it to a 160,000 capacity stadium with the Sir Kenneth Luke grandstand extending the whole way around the ground.
A second attempt to expand VFL Park in the early 1980s in time to host the 1984 Grand Final was also blocked.