Longevity is not a matter of companies, it is a matter of success.
Anyone who says the "sony consoles are kept on the market for a very long time", "Nintendo consoles always last 5 years" only looks at the surface.
Of course, the two Sony consoles that were on the market for the longest time, also happened to be the two most successful consoles ever, and THIS is why they were so well-supported, they had longevity.
Compared to them, the Nintendo consoles were moderately successful, so they got moderate support, and the xbox 1 was the biggest failure excluding crashes, so it was discontinued after 4 years.
The Wii is the next most popular thing ever, with even more momentum, obviously it will also have EVEN MORE LONGEVITY than the PS2.