If the wireless last mile option costs $500/household then you'll get destroyed by a competitor who can come in and offer the same or better service at substantially lower cost. So yes, it does matter.
I'm not sure what you mean by "overbuild" here. I mean it in the sense that both AT&T Fiber and Verizon provide services to the same homes. US policy notionally tries to encourage this (because, you know, markets solve everything) but if you have 100K homes and 40% of them get service regardless, having 2 competitors means each ISP has to recoup their costs from half as many homes.
I'm talking about wiring brand new builds for an ISP. Getting the coax, fiber, telephone line right to the home before the lawn is sodded and drywall is installed is a really fast/cheap job. It costs basically nothing to do because there aren't a whole bunch of easements and property rights problems to navigate.
Generally, a developer already owns the rights to everything so it's just working with them to get everything done. And they like it because who doesn't want an internet ready community to sell?
You end up talking $100 per unit vs the $2000 or $5000. Which is a great discount for the ISP.
Moreover, builders often pay the cost to hook homes up to fibre during construction. Locally (in eastern Ontario, Canada) I have seen the incumbent quote and get $500k to fibre up new rural subdivisions.
> If the wireless last mile option costs $500/household then you'll get destroyed by a competitor who can come in and offer the same or better service at substantially lower cost.
That's not even necessarily true. The $2000-$5000 is a one time cost, and then that piece of fiber could last for 50 years. Having to amortize $40-$100/year against a service that costs around that much a month isn't fatal. Meanwhile they're offering service for whatever maximum speed so you set your price for that $1 below theirs and then charge $10-$20/month more for double that speed which they can't offer at all. Half the customers take you up on the higher speeds and you make back your costs, the other half take the $1/month discount and your competitor is the one who gets destroyed.
I'm not sure what you mean by "overbuild" here. I mean it in the sense that both AT&T Fiber and Verizon provide services to the same homes. US policy notionally tries to encourage this (because, you know, markets solve everything) but if you have 100K homes and 40% of them get service regardless, having 2 competitors means each ISP has to recoup their costs from half as many homes.