I think the part of the answer is that in the US legal system the discovery process is disproportionately expansive and expensive, being adversarial in nature, as opposed to many civil law countries where the judge tells both parties what documents they will have to produce so that the judge can rule. Here you argue with each other why you both need to review 100k or millions of results of keyword searches. Actually an individual or very small company litigant would be at an advantage not having much in the way of records to search.