In most cases, they aren't diverting tickets directly to TicketsNow, and if they are, it's a select few. They don't need to. They sell to the public, which includes resellers (whether they be fans or brokers), and that public then sells the tickets on TicketsNow, which show up as verified resale tickets on the ticketmaster/livenation website if barcodes are supplied (or you sell directly out of your ticketmaster account). You can actually list and sell some tickets this way prior to them being available to download, as it syncs the token for the purchase and sells that, and delivers when the tickets are actually issued (tickets routinely have a delayed delivery now).
Ticketmaster makes money on every sale (fees, as well as 7%-12% of the sale amount) so it's not like they are really losing anything this way. In fact, they may make more money, since even if the tickets sell at a premium on resale, if they don't sell for more than the cut the exchange takes, the broker still loses money (which ends up in the hands of the exchange).
It is true that some artists and venues are more amenable to this than others though. Some allow the ticketmaster sanctioned secondary market (TM+), and some don't.