Except... Sega was simply returning to a strategy that helped them attain success one generation earlier. They did it almost immediately, when the Saturn was doing well enough, and soon enough in the generation that I don't think we can really say it was a knee jerk panic reaction. They set up a new division just to do PC stuff. That doesn't just happen overnight.
Also, Microsoft was releasing games on PC, including big titles like Gears, Halo, and new to them IP like Shadowrun, all through their console life. Maybe not always day and date, but there were also PC releases that had later ports to Xbox, so timed exclusivity was a 2 way street between console and PC. They even released games or licensed their IP for Nintendo DS, and even GBA. Some were published or developed by other studios, and sometimes, like in the case of Diddy Kong Racing on DS, it was a game made by a Microsoft Studio using someone else's (Nintendo in this case) IP. There were key Microsoft IP like the Madness series, Age of Empires and others released other platforms. Even before the "Xbox games on other consoles" freakout everyone had, Xbox Games Studios games made their way to other platforms. Minecraft is the obvious example, but the Ori games, published by XGS and an Xbox exclusive, ended up on Switch as well. The Switch games have the Xbox logo on the box and everything.
I guess I just can't see it as a panic move if it's something you've basically done before, have continued to do, and has a proven track record of success.
And Nintendo and Sony standing firm... Yeah, it's something they have done before, have continued to do, and has a proven track record of success for them.