It's very much in question. As much as I hate to admit that since I do not like the concept of HFT existing as it's not providing very much value to society (imo) compared to the money made. The intellectual power behind this stuff would be much better put to use for something productive.

It likely lowers the transaction costs due to adding liquidity and narrowing bid/ask spreads for small retail orders.

But indirectly it likely raises costs for institutional investors like pension funds and large ETF managers making giant block trades on behalf their beneficiaries.

So tldr; Probably fractionally better pricing for your $5k GOOG trade, fractionally worse for your VOO holdings over the long term.