Sure you can get various decent accessories from china, but for most of the basic maintainance you need to source proper components (drivetrain, brakes, tyres, suspensions) from respected brands. You can go to the LBS, let them do the work and pay a premium or you can do it yourself sourcing components online for half the price. You could also source the components to the LBS and do the work yourself but that's usually the more expensive solution. As it often happens the most ethical choice of willingly financing LBSs is only accessible to the rich.