A problem unique to Google: The best technology money can buy but few who can use it anytime soon.
That conundrum was on display Tuesday as the company, owned by parent Alphabet Inc., kicked off its annual I/O developers conference. The event showcased some impressive technical breakthroughs, including the addition of augmented reality to the popular Google Maps service and a robust new capability for the company’s personal digital assistant. The latter, dubbed Google Duplex, allows the assistant to make phone calls and carry...