Why effective technology beats paper superiority

Does the side with the technological advantage normally win, and should we fear capabilities we have not seen?

Only if technology is defined as the best fit for war, including production, repair, and numbers, rather than the best individual specification.

Technological advantage means having equipment that fits the war, not merely the most impressive individual specification. A small number of exquisite systems can lose to a larger force whose equipment is slightly less capable but easier to build and maintain. German examples illustrate how complexity and committee design can produce an impressive system that is difficult to operate reliably. The Sherman shows the converse because its crucial sophistication was industrial and logistical rather than spectacular paper performance. Armies could field, repair, and replace enough of them to overwhelm a rarer opponent that was more formidable one vehicle at a time.