My example is how it would work in the absence of any trade mark registrations. I incorrectly assumed there were no registrations in place here. Having checked, yes, the presence of a registration would greatly improve Bolt's leverage in the manner you describe.
Registering a mark with the USPTO is _absolutely not required_ to have standing for an ownership claim, even if another party goes to USPTO and registers your mark or a similar one.
The point is that although yes, the incumbent would be able to bring a claim, in the absence of a registered trade mark, a claim on the trade mark would be based on the established goodwill in the name. It would then be open to the alleged infringer to argue the incumbent lacked the necessary goodwill.
I went and read up a tiny bit and learned about the requirement of showing that goodwill has been taken advantage of. You are indeed correct, sorry to come off as argumentative. It "only" took me one back-and-forth before I went and checked my facts.
Hey, if you can't argue on a HN thread, when can you argue? In fairness it looks like protection for unregistered trade marks appears to differ on a state-by-state basis so the position really isn't that clear. Plus mere use appears to be sufficient to get a modicum of protection but on a very limited basis.
What? That is not at all how trademark works.
If Instagram wanted, it might have a shot at a protracted lawsuit, attempting to make it not worth Bolt's time to defend the trademark [0].
If that were to happen, though, I would hope that the suit would be dismissed with prejudice because in my non-legal opinion, any reasonable person would agree that Instagram is directly infringing Bolt's trademark in an area of business that is too similar for the average consumer to be able to differentiate.
[0] either by bankrupting them if they decide to defend it, or if Bolt can successfully mount a defense, it would require a large time investment by key employees like all the C-level executives, meanwhile Instagram (having more resources by far) is not impeded in its business nearly as much.