Apparently Bulletproofs can reduce the average tx from 15kb to something like 1.5kb-3kb which is still slightly larger than Bitcoin's 0.5kb but definitely a significant improvement. Would something like RuffCT/StringCT reduce that even more? I'm also curious if we would be able to prune the blockchain in the future, like Aeon or Boolberry do - although Monero can't use the same method IIRC.

Monero also stores UTXO on-disk with denormalised database indices/LMDB rather than on-memory like Bitcoin, so although their blockchain isn't growing as fast as Monero currently, they will still suffer from a growing UTXO set in time, although hard drive storage is getting cheaper every year and there's always room for more optimisations and off-chain scaling solutions.

I'm not an expert though, so I'd love if someone could chime in and correct me if I'm wrong.