With car insurance claims easily being >100k due to injuries/death/multiple vehicle collisions, what kind of monthly rate could possible cover that?

Other examples with high claim amounts, flood insurance, health care, etc.

It doesn't matter how high the minimum cost is, and you cant judge any kind of insurance based solely on that. The chance of it happening is just as important. Let's say 1% of all companies get sued for patent disputes every year (I don't know the stats on this, just an example), with an average defense costing $500 000. The insurance company also wants to make money, so let's have them charge 150% over cost.

$500k x 1.5 = $750k (amount of revenue per 100 customers)

$750k x 0.01= $7500 (cost per customer per year)

$7500 / 12 = $625 (cost per customer per month)

Now even that number isn't that high, and I assume 1% of companies getting hit with patent lawsuit per year is bigger than the real figures.