However all other accuracy benefits remain, and absolute accuracies in the sub-micron range will still be achieved in many cases. Inexpensive bearings could be used under the platform and at the motor contact points in place of air bearings or special low-stiction bearings. This would reduce the absolute accuracy that the servo could achieve, but it will still be possible to achieve micron level accuracies. If there is no requirement for rotation, one of the X-actuators can be eliminated. In that case, the one actuator would support all 4 x-axis edge bearings Beyond that, there are many other compromises that can be made to reduce cost when speed and accuracy can be traded off.
Motors can be rotary instead of linear.
Feedback can be eliminated entirely and stepper motors used instead. Drive mechanism can be ball screw, acme screw, or even belt drive. If flatness or heat dissipation is not critical, the base can be made of a variety of inexpensive materials with limited machining.