> Income and wealth after Gen X is trending down for same age groups according to your sources.

While I see what you mean, the effect seems minor at best. I wouldn't feel comfortable coming to that conclusion without more future data and comparative numbers for Gen Z.

> Another thing to keep in mind is with decreasing birth rates, future generations will have a higher tax burden to support the aging costs of the previous generations.

This does sound reasonable, though I don't necessarily know of any actual research supporting this conclusion.