Just because it is common does not mean it is acceptable. Do you have any idea how ludicrously fast computers are nowadays? Multiple cores, each running at several billion cycles per second and several instructions per cycle. If each cycle were 1 processor-subjective second long, your average desktop processor would experience upwards of 248 years per real-time second.

Frankly, our entire industry should be ashamed that anyone thinks 4-6 seconds is an acceptable amount of time to render a fucking website.