It was different in the US before ACA (Obamacare) was implemented. Before then, employer subsidized healthcare was significantly cheaper than buying private insurance on the open market. That was a major impetus to taking a full time job. Now, the employer health plans are little better than what you can get through ACA, especially if you're young and healthy and can opt for the cheaper options with less coverage.

I was the same. There's an easy enough solution to that for the company, however.

I knew a few contractors who did take the full time role despite the lower pay.