There's some further context at https://meta.miraheze.org/wiki/Community_noticeboard#Stateme... -- specifically:
> To clarify a bit on the reason behind this choice, the technical team behind Miraheze is currently 3 people (5 if you include two unprocessed resignations). Two of those three people (myself include) are currently burned out on the project and wish to step away.
There's also some discussion of possibly handing over the project.