Another hypothetical 🤷♂️ It doesn't mean it won't always be smaller either. One thing is for sure: It is smaller than bitcoin right now. So saying "its impossible for the average joe to mine it as it requires way too much data space" makes no sense (even ignoring the fact that you can still mine it without doing that using Gupax)
*because it is actually private and fungible Monero could have smaller transaction sizes too if it wanted to be a surveillance blockchain