These days a stand isn't just a stand. I'm thinking that under these stands you have a lot of player amenities, likely home dressing rooms for both men and women and the same for the away teams.
And these facilities aren't just a room with a few benches, these days they have warm up areas, individual cubicles for players, video areas etc.
This bumps up the price considerably from the old days where it was a simple structure.
Of course I may be wrong and player facilities at Penrith are somewhere else.