Macs are better than Pc, C# is better than Java, Unix is better than Windows, RDBMS are better than NoSQL databases... Why can't people just use the best tool

Macs are better than Pc, C# is better than Java, Unix is better than Windows, RDBMS are better than NoSQL databases... Why can't people just use the best tool for the job and move on... From a personal stand-point we've switched from MySQL to Google AppEngine (and BigTable). Although I find there are some major drawbacks (e.g. joining tables) not having to worry about database servers and scalability is a major advantage. That said, if MySQL becomes the best tool for a particular feature, then let it be...