It simply doesn't make good financial sense for them not to. If they didn't take a medical history, what would prevent someone with a terminal disease from buying millions of dollars worth of insurance?
However, there are guaranteed acceptance life insurance or graded life insurance policies that do not require a physical, maybe only a few health questions, if any. They're much more expensive than regular life insurance polices that do require a physical exam.
You're usually better off looking into one that looks into your health history; however, some plans offer up to $300,000 of term life insurance with no exam needed, just some health questions.
In addition, there are accidental death insurance plans that offer up to $1,000,000 of coverage with no exam and no health questions, but they only pay out a claim if you die as a result of an accident.