It is, however, worth looking at how I can so quickly and hand-wavingly come to my answer. Let's start by using a simple rule that I like to apply to this question for any sizeable entity. It's the "Can it go bust?" rule. If indeed when a Class 1 railroad or a national infrastructure operator goes bankrupt or into administration, does government let it fall over and allow the market to respond freely? No, they absolutely do not. When COVID-19 meant existing revenue models just broke, did governments let the private operators of public transport collapse? No, they backed them up with significant grant funding.

(Incidentally, the "Can it go bust?" rule works for everything. Water and electricity companies? If they fail the test, they should be state owned. Banks? Nope. Outsourcing agencies? No. Big tech companies? Decidedly not. Companies that make those little plastic bug things on a spring that pop up after a seemingly random duration? Yeah, those can go bust and can stay private. You get the picture.)

for those new to it: meet the #CanltGoBust rule
(extracts from #HowTheRailwaysWillFixTheFuture)