I won't debate on the "wavefunction collapse" ... ... since this is just a lazy debate started from a misunderstanding. Clearly when a small system interacts with a measuring device, the wave function of the small system just loses any meaning. There is only one "larger" wavefunction for both systems together. Why then should we say it has "collapsed"? Well ok, I know we need this probability rule, but let's say it is a practical rule. This collapse question has been debated since every long now, in different flavours, but this debate has really been sterile.