Good comments here and I agree with a lot of it.
Every investor is different and it depends on the relationship. Often times if they know you personally they may take it on. However, while it's possible, it's more rare. We all read the stories in Inc. about how a company got funding pre MVP, but we don't know the relationship that existed beforehand.
Most importantly, the MVP is to reduce the investor's risk. Can't blame them. They want to know where their money is going and, more importantly, have an actual vision of what they are investing in.
I work with all startups and growthups and can tell you that I've never had a client get funded without a MVP.
Moreover, the MVP shows investors that you're willing to put your money where your mouth is. If you're willing to invest in the idea, than you're really serious and they will consider taking you more seriously.
Hope this is helpful!