You dont need sequels to build your IP recognition you know. What builds your IP recognition is telling the world that these games exist, which is what Sega(who use to be really good at those type of things) have failed miserably and many sega enthusiasts had to watch idly by seeing great titles like BINARY DOMAIN, Vanquish, Rhythm Thief go by the wayside. You dont tell anybody properly about a great game nobody will buy them, so it will make no difference if its a sequel or not.
Also, Sega was in a solid position when those sequels came out. They were buying companies left right and centre. And the sequels still came out crap. It really has nothing to do with what position the company is in the games in Sega's case have suffered through a variety of reasons, a long time gap (like a decade) between the first and last game, members involved in the original game no longer being in the company or the original team being long defunct, etc etc etc. And Sega has always been a forward looking company not a backward looking company which is why they usually strive to create new titles rather than sequels of considered classics most of the time.
Clearly not, as evidenced by how not to do it by SEGA and how you should do it by Nintendo.
That was because SEGA had a very good American President who knew how to sell their products...as soon as SOJ got jealous, he left and they stumbled ever since.
I don't see sense in buying a company when you just came out of the console business and restructuring like crazy, this may have been why the sequels were awful...because the money wasn't being used on those resources?
It clearly was in SEGA's case...I am not a businessman but even I know when you need to focus your efforts in making the damn sequels good and not buying other companies up, just to close them down or sell them on.
I don't believe that different personnel made the games worse at all....if that was the case, then why do the fans clamour for sequels of long defunct games still? It's silly logic to ask for a game if the personnel no longer exists...plus the sequels were worked on by different development teams who have virtually no experience on the game they were involved in (Next Level for Golden Axe, Sonic Team USA for Nights).
We already know why we love SEGA, but you can't deny they are backward thinking when it comes to other people making better suggestions of where they SHOULD focus their efforts in (stubborn Japanese businessmen know nothing about western tastes as been evidenced by SEGA's financial downfall).
But yeah, SEGA weren't in a great position to make games after the Dreamcast Era and should have been more reserved in their games (promoting Billy Hatcher as the next great platformer, polishing semi-frequent Sonic games). Like you said, most of SEGA's key members left...that doesn't mean they should make sequels to their games if they felt like their new blood weren't ready yet.
Look at Sonic Colours, that Sonic game was finally done right after the Adventure Series...and I put that down to the team's inexperience with Sonic. Sometimes...you really do need to nurture your teams with smaller projects before trusting them with bigger ones...especially in SEGA's case where they can't risk losing money any more.
Although I am not much of a Nintendo fan, Miyamoto is training each team up to make a solid Mario game once he retires. Sonic Team were just pushed into the deep end and made SEGA lose even more money. Their games didn't have to be perfect, but if they were to put them on Sonic games, I would have put them on the handheld sector, since that was where the money was going on the DS.
You can't tell me that their marketing is poor when they were presumably poor either. They can only do so much in terms of advertisements...and if they don't live up the expectation...well...you need to get your staff members to do it for you, which is why SOA exists still.