I don't know. Could be. Maybe Nintendo does a smart thing because they recognised how irrelevant the arms race is. Seems as if the competitors also stopped trying to make new consoles, since they instead go for minor upgrades. Might be that all three have considered that we reached a point where new consoles don't surprise anybody anymore because the objective differences in graphical output vanished some time ago. If you think ahead, what is there that could differentiate your new from your old console? What's the point of new hardware when you could rather harvest profits of your current with almost no effort at all?
We do know however that Nintendo always strifes for new ways of gaming, for innovative input methods, for a higher interaction between the game and the player, and therefore reach a higher immersion. Because they like to question the status quo. They shake things up while others rest on established concepts. Funny how they are still considered to be a very traditional company, btw. In fact, so tradtional that they reject the business they are most associated with - console gaming.
Anyway, Nintendo has always defined the direction of each generation they participated in. Yes, even the current gen. Up till the Gamecube it had been arms races between them and Sega or Sony. The innovations made were mostly in regards to the controls (shoulder buttons, rumble, analog stick, Z-trigger). All of those were copied shortly after. When they shook things up with the Wiimote, others followed quickly. When they tried to introduce tablets to the gaming world, others had their respective projects ready just shortly after. Just in case it was as hot as the Wiimote. You don't want to fall behind when Nintendo shakes things up. So, when the NX hits the market and becomes a big hit (let's just assume this), others will follow. If the NX is the next revolution in gaming, there might be no PS5 or Xbox2. Yes, they have THAT much influence. And the interesting thing is that Nintendo knows this. As soon as they reveal it, others will start copying it. And that is the single reason why they hestitate to show anything currently. And it's also the reason why there are these iterational console upgrades from Sony and MS. They need to react somehow to Nintendo since they don't want to have them leap away, but they have no idea what they are supposed to react to, and they don't want to fuck their current user bases besides, so they try to resell you the same consoles again. Nintendo forces them to do something, while they rather wanted to ride on with what there is. The handling of the NX is extremely strategic as it could be another turning point in the entire industry. And because of this strategic importance we still don't know shit about the NX. As painful as it might be, we still have to be patient before anything ca be said or done.
These are my thoughts about the current situation. Of course someone might differ, but for me, it's very clear that Sony and MS shit their pants when they think about Nintendo. Finally, my answer to OP's question: I think they haven't.