Answer
Nowadays many ships do not have a prominent bulbous bow because the operating profile of ships has changed. Earlier ships were designed for higher fixed service speeds, where bulbous bow reduced wave-making resistance. But now due to fuel economy, slow steaming, EEXI and CII, ships often run at lower speed and different draughts. A conventional large bulb works efficiently only near its design speed and draught. At lower or off-design speed it may increase resistance. Therefore modern ships use smaller, modified, integrated or optimized bow forms instead of large visible bulbous bows. It is not that bulbous bow has disappeared; it is now designed according to actual speed–draught operational profile.