Most webhosts have small support teams ranging in size from 1 to 25 people. So when even 1 employee walks away, it leaves a very large hole that need to be filled quickly. It’s hard to find good people willing to work different shifts and be available 365 days a year. If you do get lucky and find one, there is still the long arduous cycle of training. The cost of training 1 person is often the same as training 20. Therefore, when you are training in small batches of 1 or 2 or even 3, you are incurring a very high cost per person.
Holiday Season is a tough time for web hosts. It is hard to find someone to man support when the regular people take off. Also, last minute leaves, sickness and other such absenteeism is almost impossible to cover because there are no backups or pool of other employees who can called upon to fill in. The same is true for weekends when it is hard to manage the support with thin to no staffing at all.
Web Hosting is a growing industry. Webhosts need to balance their time between Sales, Procurement (Bandwidth, Servers, and DC Equipment), Billing and other nuances that come with running a growing business. Managing, Training and Supervising large support teams is an unnecessary strain on his already limited time. Webhosts would much rather spend that time growing their sales and hatching productive partnerships within and outside of the industry.
It is near impossible to have round the clock coverage for most webhosts with small teams. Also, the cost of running an infrastructure 24x7 can be very high in most developed countries.
Webhosts with in-house support also lose out on the benefits of having a support vendor who has exposure to many different hosting companies and environments. Not only does the vendor keep the webhost up breast with the latest developments in the industry but they can also bring to board a host of best practices that are being adhered to by the industry. These could range from ideal response times to backup methodologies being employed around the globe.