> Especially for developing, backward economies (early-19th-century US, late-19th-century Germany, and contemporary China), ignoring foreign patents is very useful for speeding up technology transfer from more advanced economies

There is no doubt that copycats would benefit enormously from an absence of patent protection, but innovators would doubtless invest less capital in innovation if they could protect it.

Germany, U.S., and Chinese copycats were about to free-ride on the license fees paid by English manufacturers to patent holders. If the English never established a patent law, then there would be nothing for them copy and the overall welfare of society would be reduced.