I agree, but someone on the Hugo forums pointed me to this issue:
https://github.com/lektor/lektor/issues/180
The fact that it's such an egregious issue (85 minutes for 2000 posts?!) that has been open for 9 months doesn't give me much hope in the development speed of Lektor. This also matches my experience, as I see trivial issues and PRs open for months in Lektor's repo...
The Lektor dev (it wasn't Armin) told me on Gitter that development has stalled a bit, but will hopefully pick up in 2017. I certainly hope so, becaue it's a well-designed site generator.