The optimization tricks have merely changed, instead of the whole concept being redundant. Nowadays you should aspire to reduce branches as much as possible to

The optimization tricks have merely changed, instead of the whole concept being redundant. Nowadays you should aspire to reduce branches as much as possible to keep branch prediction happy. Dependent memory accesses should be kept to a minimum. Loops should be written in a way where autovectorizer can easily convert it to a bunch of SIMD instructions. One should understand what the compiler can optimize and write code that allows it to do it's job as efficiently as possible. The same principles apply as they did in the ages gone by. There is a place for scripting languages and there is a place for heavily optimized library. It's just that the way to write those heavily optimized libraries has changed a bit. Instead of hand writing assembler one just has to write C in a way that allows the compiler to do it for you. From a web development point of view this means that in general it's good to use <insert the framework that is currently fashionable> and for the parts that require some oomph it's good to have something really optimized like ImageMagick on background. From mobile perspective it doesn't really matter in what way <It's like Yelp but for old shoes with location awareness> is written but you better hope that the basic system is optimized as much as possible. Because that transfers immediately into battery life.