This is one of the problems with "decentralized" services: the expected trade price cannot be predicted during periods of
high market volatility or low liquidity. even if the pool's liquidity increases, it is difficult for small services to handle sums like $50 million, which might be better handled through centralized services. It is also difficult to ensure that $50 million is always readily available as liquidity.
The fault lies entirely with the user.
This is why i believe DEFI is still immature. There is still so many loopholes that make the executors lost their money. It gets worsen with how the money is not refundable, and aave is only giving back 600k fees to the swapper. So i guess defi is not yet ready for the mass adoption.
It is not a technical problem, but it is impossible to continue providing liquidity and imposing low trading fees. Liquidity providers will not make profits from such low fees.