Why Germany could not simply accelerate the Elektroboot

Could Germany have accelerated Elektroboot research in an alternate treaty environment?

Only with earlier access to Dutch technology and a reason to answer the Allied ASW threat that historically drove the design.

Important foundations, including snorkel technology, entered German hands through the Netherlands and were then refined. Germany could not simply order the historical Elektroboot earlier without either earlier Dutch access or an independent substitute for that work. The program also answered a changing Allied air and anti-submarine threat rather than a generic desire for more U-boats. British submarines received the same Dutch ideas but had different operational requirements and did not need the same response. Captured technology and enemy pressure jointly shaped the development timetable.