How about if borders are no longer what's being fought about? That is, the violence, the competition, the exploitation, just use different markers of territory and success? The borders won't change if that isn't where conflict is happening, that is, if they aren't doing much.
One idea I had was, you mention that corporations get stronger? That might do it. They could wield enormous influence through financial means, compete over markets and trade agreements, and - especially if these are multi-national corporations and the markets continue globalizing - generally not give a hoot where the borders are since they care about monetary resources and territoriality (profit), not land-based resources and territory (borders).
Such corporations would be powerful, as powerful as governments in their own ways. Monopolies give leverage over all those who must buy their products, especially if doing without is dangerous. Employers (especially when, in some areas, that is also a monopoly, see company towns) can also wield a lot of power over their employees, especially if they need money to live, so being unemployed is dangerous. And they might turn security guards into a security force (aka army), and internal auditors for fraud investigation and interpersonal conflict (aka police force) because don't they have a right to protect their investments, and which country should they apply to anyway when their holdings are multinational? And company rules that are, effectively, actual laws because hey, with so many people in so many countries, which set of laws has precedence and isn't this an internal company matter anyway?
And, these sorts of fiefdoms don't necessarily have to care about national borders - as long as the governments have, or can be persuaded to have, some kind of trade agreements. And that persuasion, eventually, can reach levels where lobbying by the tech companies that deal with information security on the devices the governments use (and therefore have access to information for blackmail) or else perhaps the companies that deal in hardware (like the weapons the government relies on to keep the peace) is really, ah, somewhat Less Uncertain than company lobbying methods today.
There isn't going to be a peace that leaves the borders where they are, that isn't how people work. There will be aggression, competition, territoriality, cutthroat politics, and tons of collateral damage - people will do it when they can get away with it, and actively try to shape situations so they can get away with it. But the territory may change, the limits and methods of enforcement may change, the seat of power and necessary politics might change, and if the old (land territory borders) are no longer relevant enough for the new (economic leverage) to fight over - why not leave them be? As, essentially, "historical artifacts".