For me, I grew up in the 2000s with Xbox and Nintendo in the 6th and 7th generations. When the PS4 and Xbone came out in 2013, I switched to PlayStation and its at that point that I became fascinated with gaming history and the types of games I'm interetsed in to this day (Japanese games, RPGs, etc).
When I learned that Sega used to make consoles, my mind was blown. The first year of the PS4 (2014) was very bad imo, so I learned all about the history of Sega and its consoles and the tragic downfall of the Dreamcast always resonated with me so I rushed out to buy one along with Shenmue I and II, Sonic Adventure 1 and 2, Power Stone, Crazy Taxi, etc. I then became the annoying 14-15 year old hipster guy at school whose side in the console war was "Dreamcast" or "Sega" instead of PS or Xbox.
Because of this, I have a soft spot for Sega despite not growing up with them and still having many awesome Sega games still in my massive backlog (so to me, in a way, I still get to experience new Sega games!) In the modern age though, I do feel like, as a big fan of Square and JRPGs in general, PS is the ecosystem for me, and objectively PS1 and PS2 are better than Saturn and Dreamcast even if they're a bit less exciting.
I still like Nintendo too, and with Sony's unrelentingly hostile approach to Japan and Japanese games I can certainly envisage a futue where Nintendo become my no.1 if Sony alienate Japanese devs like Square, Atlus, and Sega (ofc) too much that they decide to prioritise Nintendo and the home market.
Of course, if Sega ever do make another console (I know it won't ever happen and would likely fail if it did) then I would be there day one and it would instantly have my heart :)