Careers in research suck. Not because of the work but because of the nature of the contracts that research is carried out under. Typically these are less than 3 years and often just one. Competition is high and wages often low (a typical "hirers' labour market). Whilst working on one contract it is often near-impossible to set yourself up for another to start immediately after the first has ended. For example, one of my supervisors spent 8 months unemployed between her last position and this one- and that is not an unusual spell. She told me she met a guy at a conference recently who worked in his Dad's hotel for four years before being able to pick up another contract. This isn't to say there isn't work out there- I know people who aren't suitable for the projects they are on but got the job through favouritism or by picking up the reigns from someone who had quit. And who wants to relocate every two years or so just to stay in work? Try maintaining a relationship in those circumstances, or buying a house (not that you'd want to right now).
This Guardian article outlines the situation well.