I tend to agree with you in most situations, but I do think there are some counter examples.
The recent rollout of various COVID tracking apps for large companies come to mind. There was no way to predict the need, and low code tools were leveraged heavily to spin up quick solutions. e.g. I believe SalesForce products were used for some of the "Vaccine Finder" types of sites that spun up in my state.
That aside, as a general rule, if these are such important projects, the business should expand its development org and improve internal processes to better react to business needs.
But it seems like an almost universal problem (especially outside of tech) that this just does not happen. There is often very limited appetite to take on the risk of a big dev project without understanding its value. You could argue that building a business case is a better way to prove that value, but on the other hand, if you can build a business case by literally implementing a solution, and bring data to leadership that clearly says "this is worthy of investment, and here's a v1 already working to prove our point", this appeals to the risk averse management types since it proves the need.
I don't think this is a great mode of operation, but I think it helps explain why we see such investment and growth in these tools.