First of all good luck in obtaining all those certifications as its a lot of work especially if you dont already work in that field.

What I would say is that very few large organisations have people that perform all those roles. What you do tend to find is that larger companies employ people to specialise in a particular area but have limited knowledge of other areas. I.e a DBA who understands networking and admin to the extent they can trouble shoot connectivity issues to a SQL Server and stipulate what kind of accounts they require in AD to support the SQL Servers.

Smaller companies that cannot afford the higher paid salaries of specialists or the combined salaries of several people performing all these functions may look for someone with all these skills.

My experience with people with all the skills you have mentioned tend to have been general IT Administrators and whilst competent enough have not been able to perform any of the roles fully as it's too much information for anyone person to retain without years and years of experience.