Or may be we are approaching a wall that is harder to climb than usual.

With unlimited computing power we could render real time highly interactive super accurate simulations which takes months to render. But we can't because we don't have the computing power.

The truth is, we are hitting multiple wall at the same time. It's harder to shrink gates any further, it's harder to increase clock speed anymore and it's harder to dissipate the heat generated by the cpus. All the increase we are now getting are incremental not exponential and that is why we can run a current software on a 10 year old cpu, if the software is not optimized for multicore cpus.