wikipedia is full of errors. Sega produced GGs for that time and continued to allow development, but it was not a major contender for more than its first two years. MK and Sonic kept it afloat for a little while but I know more people who had GB's than GGs, and even I prefered the Nintendo handheld over Segas. Game Gear could also play SMS games so I think that helped in keeping it going, plus Sega continued to support thier hardware even *after* it was putitng them close to backruptcy.
If you look at the releases for the system GG wasn't at all relevent after 94/early 95. Same with Genesis, it lasted LONGER than SNES, by three years I think it was, but the last two years it was like only a hadnful of games and its first two years were all SMS or Arcade ports for the most part. so the point is Sega is better than Sony. Besides either way, Sony is in deeper debt than Sega was at the time and I HATE Sony I LOVE Sega. DIE SONY DIE DIE DIE!!!
Plus Sega split thier own market between Nomad, CDX, and gameGear, so they kinda screwed themselves.