I know that it is hard to keep watching some of my favorite shows when the actors, characters, or hosts change often. I imagine it is the same with The View. It is hard for viewers to keep watching when they keep losing favorite hosts and having to get used to new ones.
The hosts, including their opinions, professionalism, charisma and humour should impact a show for better or worse. A constant turnover of the hosts of the View, could confuse the audience (some of them have grown fond of a host who may be leaving). It takes time for a new host to establish their territory, so any changes could be risky, for good or bad.
The longer a host is with a show, the more they get to know their audience and become more comfortable in their setting and with their material. The consumers get to know the host better and may look forward to seeing them. When the View changes the host often, people don't become as comfortable.
Yes, the constant turnover of the hosts of "The View" impacts the quality of the show. However, the affect that this turnover has on the show is a positive one. The purpose of "The View" is to present a wide range of opinions. Bringing on new talent helps to expand the diversity of these opinions.