Most people don't close and open their browser between page visits, so time spend opening/closing the browser is a magnitude of importance less than time spent

Most people don't close and open their browser between page visits, so time spend opening/closing the browser is a magnitude of importance less than time spent loading the page. I'd rather have a browser that takes 10secs to start and 0.1secs to render a page than 2sec to start and 1sec for each page render. Additionally, timing externally like this ends up indirectly measuring unrelated metrics like the speed of your DNS server and internet download speed. I've seen people with particularly shoddy ISP DNS experience a 0.5-1sec swing in page load times after the DNS entry gets cached.