Two things to keep in mind ...
1. Names are generally better than numbers when it comes to marketing ... ie. consider 800 toll-free numbers ... does 1-800-222-2222 mean anything to you? -probably not. But I bet 1-800-Flowers does ... easy to remember and descriptive of the product / service.
2. Google certainly has a big influence on how people find sites, but when it comes to advertising in various venues and return business ... well, how does one manually get there? -hence, the importance of domain names, even in instances where 100% of new leads are via SEs.
The threat to domain names by other navigation methods is minimal compared to say 5 years ago when various keyword systems existed, such as AOL keywords, which for awhile was poised to potentially dominate how people find things ... but now AOL is basically just another website and I rarely ever see AOL keywords mention anymore ... these days domain names dominate.
Ron