You are comparing the cost of the building for what it gives in one collection?
Once you build the villa you can collect it every 10 hours (or twice a day if you want a more relaxed play).
That can be as much as 675k coins for an investment of 25k coin and 100k supplies (it can actually be even more).
If you develop the city fast enough you will find that even the third and maybe the 4th goods expansion make sense early on, not on the first or second day!
(I admit I opened 7 just to see what the cost progression was)
The production cycle doesn't vary so it doesn't matter that it's every 10 hours. The villa makes 4 times the coins of a rooftile in the same cycle. So you could either buy a villa, or buy an expansion and put 4 rooftiles in it and it would be the same result coins-wise (the villa also saves a bit of extra culture).
I'm not debating the value of upgrading (if there's still some days left, that's definitely there), just stating that until you have nothing left to upgrade, goods expansions are underwhelming value compared to doing an upgrade instead.
I'm also not debating whether or not you could possibly afford it, but whether it can pay for itself by the end: i.e. if you're spending 310 goods on an expansion, 325k coins and 325k supplies, you probably need at least 5 days left plus a couple days for the cost of the buildings you'd build in 1 expansion just to pay off the cost of the goods you used. Since I don't think you're likely to be "ready" to buy a 310 goods expansion on day 2 or 3, there seems little chance of it ever being a good buy. You just can't do enough in an expansion that costs that much.
The first 4 or so might be of some value if you can ramp up fast enough, be fully upgraded in the space you have, and in need of more space to keep ramping up. Just saying the later ones, no chance.
I haven't really tried a full ramp up yet, because at the start of this round villas were still bugged and I was already semi-committed to just doing enough to use up my action points - it would've been an uncomfortable distortion to rebalance back towards making more supplies so I could afford villa upgrades by the time the bugfix came through - I had already converted to making boost, which ended up being way more boost than I needed for how far i was able to get. I'll be trying more of a villa-targeted city next round to increase my action point generation. And in general trying to increase my QS balance til the last round of the championship where I'll see how far I can really push a 1-member guild