Well, there might be not-top-class riders who make a good job as a pure helper, but some are outright useless and barely get to ride. Why do these teams continue to employ them? Examples:
Tim Gudsell (FDJ): Has no value whatsoever in a team like this, and I have no idea why they keep renewing him.
Kazakhstani riders at Astana: Yes, astana have some useful kazakhstanis, but apart from Vino, most are just useless. Iglinski, Fofonov and sometimes Bazayev can do some good help, but apart from those they are just rubbish.
Euskaltel neo-pros: Euskaltel every year promotes 4-5 neo-pros from their feeder team, but most of them retire after a year or two. They just have no function in the team at all and are a waste of money and time.
Gudsell is an alright TTer and like you said hasn't done much. But a team can't have just superstars you know. Imagine FDJ if they had, Cav, Farrar, Petacchi, Greipel, Basso, Contador, Schleck's, Cancellara, Martin, and Menchov.
First of all a team runs on MONEY. And they don't have an endless supply. Teams will try to sign riders that appeal to their sponsors (Astana signing Kazakh's, Euskatel signing Basque riders).
Sometimes teams will sign weaker riders to fill a few spots or because they need workers.
1: So who do they sign instead of the useless neo-pros?
A: They sign older, more experienced riders, who want more money to do the same job. That would be a waste of money.
2: What to do with useless Kazakhs?
A: Fire them. As Astana are doing this season (well, they aren't renewing a couple).
3: Whats up with Tim Gudsell?
A: He's been injured season after season, and unlike some teams, FdJ has done a very honourable thing in keeping him in the team, waiting for him to find his form again and fit into his role in the team - domestique mainly.
4: Why do some teams have "useless, who barely ride, riders"?
A: Because all pro-tour teams require 25 riders minimum, if I am not mistaken. So, if on a tight budget, who do you sign to fit those spots? Yes, that's right, some really young/"useless" riders who can do little more than fetch water bottles.
Or, in the case of some Italian teams, just register your mechanics as riders.
Simples. The answers to your questions are fairly simple and easy to see.
