Alphabet’s stock is down more than 15% from its May peak, wiping out roughly $700 billion in value, as concerns rise over its mounting AI bills and failure to produce a decisive technological breakthrough.After leading the Magnificent 7 over much of the last 16 months, the tech giant is on shakier footing, having seen its top scientist depart, its brightest AI mind move to a different position, and delays to its newest Gemini model. But Google retains a superlative product suite, a “deep bench,”...