Why did Japanese comics begin to decline after entering the 2 1 century?

Dragon Ball, Saint and Robot Cat are already unsurpassed classics. In fact, Japanese comics have not regressed or anything, but these three classics are hard to surpass. Look at their contemporary works. It's hard to find one that suits them. . . But now Japan is becoming more and more commercialized, and I feel the same way. Look at typical designs and plots to meet business needs. I have a stomachache. . . But the whole is still improving. . . I just can't keep up locally. . . There are also robot cats and dragon balls, as well as saints. Although they are all excellent, they are not very inspiring. . . . . . .