The problem is, trump is an idiot. He supercharged a hot economy with tax cuts, which will raise interest rates. He is also planning a 1.5 trillion dollar infrastructure plan where the guv will only contribute $250 B in actual funds. That means states and private industry will have to issue bonds to raise the rest of the money. That will also raise interest rates.
If interest rates rise, money will have another place to go. Investors hate cash right now. It's next to worthless. As soon as the market levels off, it goes right back in.
If interest rates rise, and infrastructure spending causes a lot of high quality bonds (many interest free) to start competing for investment, the market will fall, and not by a little. A trillion dollars will move.
But higher interest rates will hurt consumer spending, which will hurt revenues.
We might end up looking back fondly at 2007.