That's not entirely true.
Yes, that's all the optimisation Sega ever did, they were particularly bad. Until the Saturn actually, when Sega started to optimise well on some mid-gem titles (VF2 was great). Sony was also almost universally awful, almost no games on any Sony consoles were ever PAL optimised (until the PS3 where it became HD and irrelevant). Strange how PAL territories overall embraced the companies that treated them the worst, optimisation wise (goes to show that most people don't even notice).
80% of Nintendo first party games were speed and music optimised on all consoles, all the way back to Super Mario Bros, Metroid and Zelda. ALL SNES games had the correct music speed, because the sound chip ran on a separate clock, and quite a lot had resolution adjustments to fill the screen and speed adjustments. There were some odd exceptions, like the half optimised Kirby's Adventure, and a few early N64 games like Wave Race. And many N64 3rd party games were too. PAL GCN games almost universally had a 60Hz option, though unfortunately it replaced the progressive scan option. Some GCN games (e.g. Metroid Prime 1) the PAL version is the best because it runs at a higher resolution - it's a true 576i, with 20% more lines rendered on screen.
Overall a mixed bag, and PAL is not how the games were originally designed so I don't use it at all anymore (except the odd GCN). But Nintendo truly treated PAL by far the best in terms of optimisation.
