No. Most of the municipal proposals I see are open
access, even with a PON design.
In South Africa (we don't have city-owned/operated fibre access),
all the major fibre operators run a GPON network. They all provide
open access to the ISP's they partner with. So far, it seems to work
well.
I'd say only one of the fibre operators is not an ISP (there may be
more, it's a big country). The rest are, but they run the businesses
as a silo so that they are fair to both their ISP divisions as well
as the 3rd party ISP's they partner with.