I wonder why Sony and Microsoft still follow the traditional model where they reveal new consoles like 1-2 year before release, is it because those companies are more willing to placate investors by announcing new hardware as soon as possible even if it negatively impacts sales on their current consoles?
This is sort of a question of business models, which might be a little off-topic here, but I think it boils down to their mutual competition, the kind of a product they're making, and the sorts of risks that these companies are willing to take.
On the mutual competition side, they really need to be matching each other on releases as closely as possible because these consoles have been the most direct competitors for generations now. If Sony lets Microsoft launch their next gen console significantly before, that could risk losing playstation owners who want next gen now. And vice versa. But also, launching significantly before might cause problems with getting the AAA publishers of the world really leveraging whatever new capabilities they have. So for both companies, they want to launch at almost the same time, but just before the other, which leads to an incentive to
announce earlier to get that edge. and that flows to an equilibrium of launching uncomfortably early
On the product itself, these consoles haven't really changed qualitatively over the years because the design has matured. The controllers are (almost) the same between generations, and there's no "gimmick". Nintendo as we know likes gimmicks (which we love), and a gimmick makes it really important to make a big splash and not leak anything to get the biggest surprise in the marketable period. Sony and Microsoft don't have that incentive, at least to nearly the same extent. Oh, a new Playstation was launched? Ok, I'll mentally increment the register where I store the current generation. Out with PS5, in with PS6.
On the risk side, announcing early has the downsides of setting a timer and the conditions for a crunch in the run-up to release, as well as cannibalizing existing sales. The audiences for these consoles are not the same "blue ocean" type of customers that Nintendo spends a lot of effort and attention on, so I don't know of how many new system sales they expect to make in the run-up to a new generation anyway. Also, the sorts of games that people buy for their Xbox/Playstation are not necessarily the kinds of games that are so easily cannibalized. Think of the number of annual or near-annual AAA releases, and think of sports games which are only meant to be played the year of their release. And regarding the timer and crunch, I think their respective pedigrees in consumer electronics (sony) and the cut-throat american technology industry (microsoft) means that they're much happier to take a big swing well before mass production has begun.