60+ ready PRs in GitHub, and very slow speed of merging

Is there a reason for this, besides little free time for checking?

merging sux?

There’re very few contrbutors with merging rights. And only a few of them are active.

For my part what little time I’ve had recently has been taken up addressing a really tricky compilation issue, probably something like 10 hours to address it.
The good news is I got it sorted out, and did a big batch of merging today, the pending PRs are down to 40 and I’ll be looking at merging still more.