You can use something like Salesforce as an app platform if you want. It lets you create "Custom Objects", which are basically tables, write queries, and so on.
It's just that the hassle of dealing with that platform tends to be similar to the hassle of setting up an app yourself, and now you're paying a per-user license cost.
Even Salesforce doesn't have a good way to quickly port an Excel-based workflow, with file handoffs and backwards compatibility, into Salesforce. In theory, you could have an LLM generate all the metadata files that would execute a relevant schema migration, generate the interface XML, and build the right kinds of API calls and webhooks... but understanding what it's doing requires a Ph.D. in Salesforce, and many don't have time for that.