For those reasons:<p>* Physics stopped CPUs from advancing any further.<p>* When CPUs used to advance they almost cost the same, that&#x27;s why once they reached a new milestone they never looked back to produce slower CPUs.<p>* Adding a number next to &quot;i&quot; will make costumers pay more for pretty much the same CPU.<p>* There&#x27;s only major CPUs manufactures and all CPUs they make are sold anyway so they start by mass production from day one.