I kinda disagree, but it depends on the product/market. You can't pre-sell a nuclear fusion reactor before it's built (I'll bundle that with my swampland in Florida!) but there are ways to generate meaningful traction through list-building, pre-launch sales, commitments, etc. for SaaS apps that you could use to raise money. And frankly, that's what an entrepreneur should be doing in the first place to validate that you should be building that product for the target audience in the first place or that there is a market for your product. And you can always strip down your MVP to it's absolute core to get it out the door faster so you don't spend 6 months building it.