Winning is not what he's about, never mind what he says. His ugliness will persist through election day.
Declaring that he's suspending his campaign would only add to the ignominy he will suffer. He'd be known as the presidential candidate who quit <3 weeks before election day, has that every happened before? I don't think so. The thrashing and gnashing of teeth will persist and intensify. The next debate will likely be the ugliest, most despicable. The Democrats probably have more ammunition in reserve, but it's apparently unnecessary to use it.
Trump brand is suffering. He's making plenty of enemies now. Myself, I wouldn't buy anything Trump branded, ever, be it a presidential candidate, a bottle of wine, a hotel room, a tie, you name it.
Trump network? That's a risky affair. It would take a lot of money, a solid backing I doubt he's going to get. There may be a large population of unstable people cheering for him now, but how solid will that base be going forward?