Unfortunately, there is nothing to prevent someone from building a layer on top of a blockchain and issuing tokens that are supposed to be backed by deposits and then running a fractional reserve. (Many accuse Tether of doing just that.) Furthermore, blockchains have difficulty scaling. That is why BTC has resorted to the lightning network to attempt to address the scaling problem.
So BTC is a solution, but it's really not a solution because someone can come up with a different solution on top of BTC which wouldn't really be a solution at all, thus making underlying BTC not a solution. Think i got it. And then BTC is having problem scaling so that's why they introduced a scaling solution called LN. Did i get it right?
If the solution you want is to totally prevent people from running fractional reserves, then no, the blockchain is not the solution. Perhaps if you could cram all of the functionality onto the blockchain itself it may be a solution. However, when you try to cram all of the functionality onto the blockchain itself, you run into a scaling issue. You can get a blockchain to scale, but this always comes at the cost of the network being more centralized.