Given that the median transaction sizes are so similar between Monero and Bitcoin ([see this question][1]), what other contributions are there to the overall blockchain size (e.g. database overheads or other Monero-specific contributions)?

I ask as someone not terribly familiar with databases and blockchain storage codebases between different cryptos. I don't see why there is so much concern over Monero's scalability with respect to blockchain size if the median transaction sizes are so close, unless there are other factors I am not aware of.


  [1]: https://monero.stackexchange.com/questions/211/how-much-larger-are-monero-transactions-compared-to-the-average-bitcoin-transact