Alan Sugar is a product man. With Tom, he can see the products - knows the sort of business partnership he will have. Tom clearly has skills as an innovator/inventor, add that to the business aspects LAS brings to the table can bring success.
With Melody - I think fundamentally, LAS couldn't see what the business would be, and one key thing Melody lacked was the clarity to say what she actually did. Her CV boasted of many accolates, but didn't count for much in the final assessment.
Over the past few weeks her business instinct has been wrong, such as:
1. Manipulating the results of the Paris focus groups to get the outcome and product she wanted, and also failing to provide her PM with information regarding the major retailer they were pitching to.
2. Biscuits as the new popcorn - that nobody liked. The idea of a role-play in the pitch (where were these made - in heaven?) etc.
3. In the last task - failing to buy products that would sell in favour of items she liked the look of.