In what way is not running 32 x 1Gbps over GPON over engineering?
For a "home" 1G service, GPON with a 32:1 split is fine as long as you accept a CIR (guaranteed minimum download speed) of 75Mbps.
The current household average superfast usage is 223GB per month, which works out at an average of about 0.7Mbps.
It is bursty of course; however the chances of all your 31 neighbours all being at home at the same time, let alone them all using more than 75Mbps at the same time, are pretty slim.
Even in the event that five people are caning the link simultaneously, then they'll each get nearly 500M, which is not bad.
And since GPON and XGPON can coexist on the same fibre, individual customers can be upgraded if they really want more. Most people are unlikely to want to pay the extra on day one.
Same applies to backhaul links: you're not going to provision a separate 10G of backhaul for every 32 users.