A classic writer issue. Renraku was driven in a corner as the "Seattle arcology megacorp" from 1998 to 2005. When Brightlight, Deus, Megaera and Sherman Huang were out, and the arcology seized by the local government, there would obviously be a void.
MCT and Neonet were given the AI interest precisely to stop it from a being Renraku exclusive domain. The "Japanese megacorp" angle always has been overcrowded, with MCT (Yakuza megacorp), Shiawase (Shinto megacorp), Evo (East European-Japanese melting-pot) and even smaller players Monobe (random Japanese megacorp #1) and Yakashima (random Japanese megacorp #2).
Renraku would have to be reinvented. But freelancers already have their hands full (or more precisely, made their hands full) with Horizon as a whole, Aztechnology war, Ares and Neonet internal feuds, artifacts... Renraku currently lies in the same "take and use as you wish" hole where Federated-Boeing, MCT, Shiawase or Cross have been serving their time.