Straight raked bows are popular because they are cheap to make, not because they are higher standard.
The curved clipper bow is more desired than a straight raked bow, but also more expensive to build. It is better than straight raked bow to keep waves to reach the deck in rough sea state. It also greatly increase buoyancy when the bow dips into the water. Many older built Navy ships choose this type.
Straight raked bow becomes popular in the Navies because it is easy and cheap to build. Just weld flat straight plates together, you get a ship. While to make that curve of a clipper bow out of steel plate, one need the huge press machine. There was a documentary recently talking about that press machine and how the Type 055 ships' clipper bow is made out of it. That machine can make any curve the designer want because it is computer controlled.
Prior of 055, the 052xs are using straight raked bows just like US Tico and Arleigh Burke.
The only advantage of Straight raked bow over clipper bow is that it has a little bigger volume at the bow which is preferred by commercial ships like most of the new yacht.
The reason for modern bow design is 100% dealing with hydrodynamics, buoyancy, and stability, relating to what type of ship this is, and what's the most efficient for this type and purpose of ship. It has nothing to do with cost. There are bow designs more efficient for 'fuller' designs such as bulk freighters, tankers and ULCCs that would displace up to 400,000 tons, and there are bow designs suitable for warships that displace 4,000 tons. Building the bow section of the ship is far from one of the costliest contributors to the ship, and for a warship, its about its sensor, management and weapons systems.
Bow designs change and continually change because engineers are still perpetually searching for the perfect hydrodynamic bow design given a ship type or purpose as requirements for fuel economy and other things continue to tighten.
Most raked and clipper bow designs are generally accompanied by a bulbous bow, so its never a simple geometry anyway regardless of how it looks above the water. For warships, the bulb would contain a hull sonar but for merchant vessels, the bulb is hydrodynamic reasons only. With warships, the bulb tends to be more rounded or full at the bottom, while on merchant vessels it tends to be more fuller and rounder at the top. This has nothing to do with cost, but because merchant vessels are considered more 'fuller' designs with a much higher weight displacement.
