If I pre-filter the data and collect only the answers to questions I’ve already thought to ask about, I can't come back and ask different questions of the data

If I pre-filter the data and collect only the answers to questions I’ve already thought to ask about, I can't come back and ask different questions of the data and get those questions answered against the historical dataset. (I'm arguing for why they might choose to do it this way, not arguing that that's the best balance point for the system. I'm sure that laziness has a factor here as well, as "ship it all to the data warehouse and we'll figure it out later" has a certain appeal in project timelines and is often the default stance.)