One constant trend has been that soldiers are less expendable. In the first world war, sending men to walk slowly towards machine guns and throw a grenade if they survived to get close enough was their patriotic duty. By Vietnam, having large numbers of soldiers come back in body bags was politically unacceptable.
The Great War was a major reason that soldiers became less expendable. That war saw millions of casualties in a single day, multiple times, with none of it able to break the stalemate. In World War II, not one of the powers was interested in making the same kind of sacrifices, with technology making up the difference. Bombers and tanks prove more effective than meat anyway. But most importantly, ever since the end of World War II there has not been a single conflict that directly threatened the West. Sure, the Cold War propaganda had most of the country convinced that Communism as an idea was spreading and threatened the American way of life. But nobody seriously believed that the Veit Cong were even capable of (let alone interested in) mounting an assault on our shores. Neither were they likely to have any impact on any of our European friends by the 60s. Body bags are politically acceptable when the propaganda makes clear that they died to protect our lives and sovereignty. Not even propaganda could sell that message about Vietnam.
In the 1940s, Japan was flying aircraft loaded with bombs into American warships. A few years later, people realised [sic] that you could design aircraft for this purpose and make them a lot lighter and able to accelerate more if you removed the human pilot. They called them anti-ship missiles.
The first missiles were designed and deployed by Nazis before the Japanese got desperate enough to launch suicide attacks. I highly doubt that kamikazes had anything to do with their development.
In the next generation of ships a lot of this will be replaced by lasers, which reduces some of the resupply need
Megawatt lasers are a really cool idea but I doubt they will be ready for the "next generation". The power costs are enormous even for the working models we have now which don't have enough destructive force to blow up an attacker like a well-aimed missile. Energy weapons ultimately aren't practical without free energy.