Probably not billions. Each person (at a 40-hour workweek) works about 2000 hours a year. V8 has been around for about 16 years. 1 billion hours would mean (1 billion / (16*2000)) = 31,250 people full-time on V8 optimization. A google search seems to suggest that the actual headcount for the full V8 team (not just the optimization team) is probably in the 3-digits.