You know splitting a site is basically just add another junction linking to a different URL. You can do that in ten minutes. THe real problem is the hoster. Regardless if they have 1 or 100 different sites.
So the strategy of more sites has absolutely nothing to do with this.
Well it is only indirectly their fault by chosing a bad hoster apparently. Like when your internet at home fails. Very annoying thing. I am afraid VHTV can nothing do but wait til hoster fixes the problems. Usually you have a 12 or 24 hrs support contract with those hosters. Better hosters usually are faster and have less downtimes.