Yes, there were walls back in the 90s and yes, we managed to break through them. However, the walls we face today look much nastier. I concede that there's no way to know the future, but nonetheless I'd put my money on a sharply slower rate of improvement for CPUs.

In the short term, it would be great if we had a breakthrough in x-ray power sources (for cheaper EUV lithography), a breakthrough in etch control (for vertical transistors), or a breakthrough in III-V materials (for a one-time mobility improvement).

But long term, we need to find an alternative to the transistor. Perhaps spintronics, perhaps non-von Neumann architectures, who knows. But there is no way that a paradigm-changing redesign will be competitive with silicon in the next 10 years. Silicon has a humongous advantage in manufacturing, supply chain, know-how, scaled production, etc. Even if we find a better technology (and we haven't) it may still take decades to get there.