Maybe, except some of them don't have that option.
One gave up working for Tesco. I think he mentioned on the last episode how he resigned to go on the show, so he'd have to find a new job or live on savings for 6 months until the BBC let him find employment.
The other four own existing businesses already. They all developed business plans for a new business that they believe in. €250k isn't actually a big investment - there are plenty of other investors who'd put that into a good plan. A bit of googling and you can make an educated guess what those businesses were. All except Joseph Valente.
I know that in their shoes, I'd get started with the new business idea. Just because Alan Sugar liked another candidate better, it doesn't mean that the losing candidates are a waste of time.
What i find incredible is the statement upthread that the quality of the business plan is not the main criteria to deciding the winner!