For projects of importance, you need divergent skills to succeed. It is not possible to find an individual with all of the skill sets needed, nor would you want to. To create a first rate website or software product, you need many tasks to be done in parallel, which means that more than one person has to be working at them.
Having been on several 'projects of importance' on teams of diverse experience, this point has been driven home, repeatedly. The continuum of experience, from those who know far back end to UI dweebs, will hopefully include sufficient experience overlap. That overlap fosters effective communication thru mutual understanding, and contributes to project success. Employers need to realise this fact and get realistic with their job ads.