It's really a problem of money though. The DNC really are the king makers when it comes to candidates. That and PAC money are the requirements to get a nomination. At least when it comes to presidency. Smaller elections you get more freedom to have a successful without such things. The whole system needs an overhaul unfortunately and I don't see any candidate from any party looking to fix that any time soon.
That's only problem in the USA. Other western democracies are able to have snap elections done in two months.
The first couple states really end up determining who usually wins the nomination and financial backing. It takes time to move a candidate between places and set up multiple events and fundraisers. Now in state and city elections the US can do those quickly as well. Smaller area to cover and campaign and the community stays informed. It doesn't help that national elections involve institutions like the electoral college instead of a popular vote. That's a different problem though.