But in any optimization scenario, you eliminate bottlenecks first. I question whether the ISP to home link is the bottleneck in the modern internet experience the way it was in 1998.
You're right about that, but I think it isn't purely an optimization scenario. Altogether new use cases emerge when your workplace and home are linked with such dramatically higher speeds.
Even more new scenarios shake out when work, home, and most of your friends' and family members' homes are so linked.
When connections get orders of magnitude faster, it becomes about doing new things, in addition to doing the old things faster.
I surf the web the same way with 1Gbps fiber in Tokyo as I did a few years ago with 3Mbps DSL in Ithaca, NY. But surfing the web is just a small part of what I do via the Internet nowdays.
But in any optimization scenario, you eliminate bottlenecks first. I question whether the ISP to home link is the bottleneck in the modern internet experience the way it was in 1998.