The primary reason why TVs cannot "watch" 3D is due to the limitations of current technology and the way 3D content is produced and consumed. Unlike traditional 2D content, 3D requires the creation of separate images for each eye, which must be synchronized and presented in a way that the viewer's brain can interpret as a three-dimensional image. This process involves complex technology that is not yet fully integrated into standard TV systems.

One of the main challenges is the need for specialized glasses that synchronize the images for each eye. These glasses use polarized lenses or shutter technology to ensure that each eye receives the correct image at the correct time. However, this requires a significant amount of additional hardware and software development, which is not yet feasible for most consumer TVs.

Additionally, the production of 3D content is more complex and expensive than 2D content. Filming in 3D requires multiple cameras to capture the separate images for each eye, and post-production involves additional steps to ensure the images are synchronized and the depth perception is accurate. According to a report by Statista, the global 3D television market was valued at approximately $3.3 billion in 2020, indicating the significant investment required for 3D technology to become mainstream.

Furthermore, the human visual system is not designed to process 3D images continuously for extended periods. Prolonged exposure to 3D content can lead to eye strain, headaches, and motion sickness, known as "3D fatigue." This is due to the brain's need to constantly adjust to the alternating images for each eye, which can be tiring over time.

In conclusion, the limitations of current technology, the complexity and cost of producing 3D content, and the potential health risks associated with prolonged exposure to 3D images are the primary reasons why TVs cannot "watch" 3D. While advancements in technology may eventually overcome these challenges, it is not yet feasible for TVs to incorporate the full capabilities of 3D viewing.