LCOE also does not account completely for time effects associated with matching electricity production to demand
I am unsure why you bring this up seeing as how nuclear power can not react due to load demand and instead only provides base load power, which means other power sources are required to keep up with transient demand.
The network effect is one reason, if users are responsible for the content then there will be a shortage of content until enough users join.
Beyond that, humans are social creatures and want to fit in. If your community mainly hangs out on one platform, people will want to be a part of that platform. What helps is if people with a large enough following or entire communities make the decision to change platform, but that can be tricky.