Building something users love is, of course, the challenge. 99% of startups are unable to do this, and some of those that can't still manage to raise money because someone involved went to Stanford or is otherwise well-connected, only to inevitably fail later on. Generally speaking, these days if you don't have rabid fans of your product almost immediately among some group of users - however small - the product as you have implemented it is destined for failure.
If you fail to attain at least some group of rabid fans right after launch, then you have to ask users and find out what changes you could make that would turn them into rabid fans - if anything. If you don't get some sense of agreement among users from the responses, odds are that you should move onto another project. Products that the masses love are very rare. Creating them is hard, and because it involves a tremendous amount of subjectivity and pure luck, it will likely take far more than one try. But you can only fail at it if you stop trying or let yourself get bogged down with attempting to make something work that users simply don't and will never care about.
VCs are optimizing for something other than love. They're optimizing for potential scale. You can build a product that customers love, but with a low ceiling for the market (like, say, building a really awesome surfboard). VCs want to see billion dollar market potential. So they may invest in something without real proof of customer love, or even customer need, just because the market potential is great.
That might be true at the seed stage, but no competent VC is going to keep funding you if you've launched and aren't able to demonstrate that some people love your product.
Of course, product/market fit is not a sufficient condition for success. You also need the market to be big enough.
On the other hand, the OP's assertion that money just flows to people who "look right" (my words, but true) without real regard for the product itself, applies largely to seed money only. A proper Series A round (or more) should require a strong product and customer feedback. So I think my point still holds. Seed VC is looking at market opportunity and founders who "look right", not a killer product that customers love, because the product may not exist or have a significant customer base yet.
If you fail to attain at least some group of rabid fans right after launch, then you have to ask users and find out what changes you could make that would turn them into rabid fans - if anything. If you don't get some sense of agreement among users from the responses, odds are that you should move onto another project. Products that the masses love are very rare. Creating them is hard, and because it involves a tremendous amount of subjectivity and pure luck, it will likely take far more than one try. But you can only fail at it if you stop trying or let yourself get bogged down with attempting to make something work that users simply don't and will never care about.