[theideaofcoffee]

Let's be generous and assume that we need far more reach than what is realistic in this scenario, take it at 10km between the subscriber demarc and the CO where these connections would presumably be terminated. A 10km LR optic is only $27 [0]. Amortize that over, say, three years and that's $0.75 per port, multiplied by two, so call it $1.50 per port/month over three years. Scantly driving up the cost per port. The physical fiber linking the two ends is more expensive (though you could depreciate and amortize over a longer period of time).

The 25G optics are barely that much more, LR/10km for $59 a pop. [1]

[0] https://www.fs.com/products/74670.html?attribute=4254&id=290...

[1] https://www.fs.com/products/75297.html?attribute=740&id=3417...