Well... I was being generous with time based on running an optimal custom learnt setup, using NGINX.
If you want to run your own cPanel setup, then an hour, and you're done. Enable PHP-FPM for each site, viola. No more managed cPanel costs. No more noisy neighbours using KVM or equal virtual systems. One line of code into your terminal and cPanel will auto install for you. The majority of security is default set. A few minor tweaks to tighten cPanel security, then you're on an auto update regime from cPanel themselves -- no security issues, no hard learning, no managed costs. If something goes wrong with the system, a ticket to cPanel and they will fix it for you as part of your license. Managed hosting without the managed costs using cPanel or Plesk.
A cPanel VPS license is $20 month to month or $200 per annum. Add that onto a $10 a month Linode / Droplet you now have a secure server setup that will run 50 to 100 online per second, depending on add-ons. Plesk is about half cPanels pricing, last time I looked.
There is no reason to pay for managed hosting if using a control panel, which most will nowadays.
There is CentminMod for those who want a free / cheaper option with more flexibility by using a single line install system via command line with optioned panel, auto update security issues and such too.
There is just no need for even a novice to use managed hosting any longer for larger scale sites, or where you want total server control and known load.
Sure... if all you need is shared hosting, then yes, managed hosting is the best option. Once your site gets to VPS level, nobody is better off on managed hosting for the long term... not with the offering available now. Again... cPanel license includes management if anything goes wrong, so why pay a managed provider for what cPanel will do as part of the license? Cheaper than a retailer when you add total VPS specs and control?
A couple of months applies only to those who want to take on the learning of a minimal install for optimal server efficiency. If you're happy with a control panel type setup, usually one line and all the hard work is done, along with the future updating of software and security.