Your premise is somewhat flawed--over the 20th century the U.S. actually increased consumer protections, though it had also provided for more protections of owners of corporate entities. I am a third year law student who had studied the history of US tort law, including products liability.

First, around 1916, judge Cardozo established that privity of contract is not a limitation on products liability suits. This expanded liability of retailers to include harms caused by their products to foreseeable third parties who had not purchased the product. See Macpherson v. Buick Motor 217 N.Y. 382, 111 N.E. 1050 (NY Ct of App 1916). Further, liability for upstream defects was extended to all entities in the vertical chain of distribution. See Vandermark (1960s), available at http://repository.uchastings.edu/cgi/viewcontent.cgi?article=1835&context=traynor_opinions.

Additionally, two facets of the US system make it a superior consumer protection regime as compared to most if not all European systems: the American rule and class action litigation. The American rule refers to the fact that for each side pays for their own litigation costs (which has some exceptions in the US that are inapplicable here). Imagine if, as a consumer, you'd have to pay for the defendant's attorney's fees if you lost your case; this would make you much less likely to sue in the first place. Throughout much of history and even today, European litigation requires the loser to foot the bill for litigation, though this may be changing in some countries. In the US, however, the traditional rule is that each litigant pays her own way. See rule 54(d) of the FRCP.

Class actions have historically been a largely American phenomenon, and class actions facilitate consumer litigation that would otherwise be of such low value (even if they win) that the transaction costs of litigating a case would be greater than the expected payout. See FRCP 23.

Last, US courts have allowed higher damages awards historically than European courts, affording a greater protection to consumers by deterring companies. Punitive damages are permissible in the US, and have historically not been available in Europe. See https://www.michbar.org/file/barjournal/article/documents/pdf4article2875.pdf.

Edit: fixed some formatting and typo issues.