It's not feasible though.
We could, but where are we getting the extra bums on seats? If you take away the history, and the memories (which we all have in abundance), Goodison is still a logistical nightmare. It's a 20 minute walk from the nearest station, and whilst there are busses, the routes are limited, so it's not accessible for everyone from the City (I imagine those from over the water, it must be even more difficult).
If we did what Liverpool did, and buy up the houses and let the area run down (something I never think we would do - I know we own some houses), and maybe bought the school, you could extend the Bullens, The Gwladys St would need every house knocking down, and the Main Stand is already lopsided, we'd struggle to meet the proposed capacity.
I love Goodison and it'll be a very, very teary day when we leave, but logistically, there's no way we can build a suitable stadium on it's site, within the same budget, as good as what BMD would be.