Progress of science is greatly enhanced when scientists collaborate intensively. The public at large believes so. To them the scientific community is one great society of people that are nice to each other, that are willing to help each other and are willing to share their insights. Collaborations will speed up the time it takes for the world to get at the Truth.

Forcing scientific collaborations upon scientists is one way for politicians, science policy makers and science managers to manipulate scientists. In their eyes the self-serving of prima-donna scientists leads to a waste of tax-payers money. It is the big ego of scientists that sits in the way of scientific progress. 

Look at the all the programs of the European Union or of Nato. In these bureaucratic institutions scientific collaborations are goals in themselves. The more partners you find in more different countries the higher your chances are of getting their support.

If you fall in this bureaucratic trap and take all these collaboration requests seriously you will end up spending your scientific life in restaurants all over Europe negotiating with local operators who have given up doing science a long time ago.