The corollary to Moores law, that computers get twice as fast every 18 months, died by 2010. People who didn't live through the 80s, 90s and early 00s, where you'd get a computer ten times as fast every 5 years, can't imagine what it was like back then.
Today the only way to scale compute is to throw more power at it or settle for the 5% per year real single core performance improvement.
- Running up single-core performance through increasingly sophisticated core design and clock speed (which is now at the 5% per year point mentioned)
- Going wider by throwing more SMT, more cores, and larger caches at the problem.
Assuming here that x86 was the last major architecture that was going for high single-thread performance at all costs, the first phase lasted us a good 30 years-- from the 4004 to the flameout of Netburst.
We could consider the second phase starting when they started delivering the P4 with Hyperthreading, and its true-dual-core predecessors shortly thereafter, so we're now about 20 years into that era.
Today the only way to scale compute is to throw more power at it or settle for the 5% per year real single core performance improvement.