You think the real downfall of the 49ers started when Eddie DeBartolo was forced to sell the team due to legal troubles off the field?

First off, Eddie did not sell the club. When he and his sister Denise split up the family corporation, he gave her the Niners, and took the shopping malls. There is a lengthy quote from him on the subject in the link below.

But in regards to the fortunes of the Niners, a lot of it can be pointed to the transferring of the team to the Yorks. When the Yorks took over the team, there had been only one Super Bowl title for the Niners in the previous 10 years. They felt that they had been saddled with an overpaid and underachieving coach in the guise of Steve Mariucci, and eventually used the excuse of a second round playoff loss to eventual champs Tampa Bay to fire him, even though he made the playoffs in four of his six seasons. The Yorks set out to find a "proper" coach, who had the same viewpoint of a proper football team that they did, and that the Super Bowl trophies would start rolling in again. They hired three of them: Dennis Erickson, Mike Nolan and Mike Singletary, and those three idiots racked up a cumulative record of 45-82 over eight painful seasons.

What was hidden from most (because Singletary was the worst coach ever) was that the Niners had a pretty solid team at the end of that string, from a series of successful drafts. Enter Jim Harbaugh. While it is true that Harbaugh got the best out of the team, and took them to the playoffs three straight years, he was also known for working his players to death. Every year he would say the team is closer to being "his" team, and not one he inherited, and every year the Niners record got a bit worse. When his "handpicked" team fell to 8-8 (and he gave up on the team in Oakland), he was out the door. His abrasive nature had gotten to be too much for a .500 coach. But the real problem here is neither Harbaugh nor the GM, Trent Baalke, would know a good draft pick if it bit them. There are only four players left on the team from the group that got screwed in Super Bowl 47, and the people that Baalke and Harbaugh drafted as replacements are probably the least talented bunch in the league.

Jed York has spent a lot of time talking to Uncle Eddie about the team, and one bit of advice that he listen to was to get good football people, and let them run the show. Unfortunately, Jed is as bad at finding good football people as his folks were. In fact, if Eddie had not bumped into Bill Walsh, they would never have found any good football people. Jed has made some good decisions, and with the building of Levi's the team is now the fifth most valuable in the league. But he is too buddy-buddy with Baalke, and he needs to fire Baalke and find a real football mind to start rebuilding the team.

Yes. The people running that organization now don't know what they're doing

i would say thats an understatement

yeah, bad ownership = shitty club.