Liquidity isn't just about there being _someone_ willing to buy or sell; it's about the spread. Do you want to go back to 25 cent spreads from the early '90s? Most spreads today are 1 cent. If you're happy paying 25 cent spreads to get rid of automated traders, I'd say that's a bit like chewing off your arm to swat a fly. Most automated traders make anyways from 0.1 cents to 0.5 cents per share. Comparatively, retailers like E*Trade charge customers $9.99 for trades that average around 400 shares, which is 2.5 cents per share. Mutual funds like Fidelity often charge 1 to 2% management fees on investment, which is 30 to 60 cents per share on a $30 stock.
Trying to bend the rules of the market to wipe out a segment that makes 0.1 to 0.5 cents per share is silly when there's zero effort concerning E*Trade making 2.5 cents per share, or Fidelity making 30 to 60 cents per share. Professional services like Lime (a high-end version of E*Trade) charge 0.1 cents per share. No one is angry that E*Trade charges 2.5 cents per share while Lime charges 0.1 cents per share? Oh, that's right, because it's "only $9.99 !!"
That's the irony of all of this. The average person writes of $9.99 to E*Trade but the media tries to get them concerned about "costs" that are effectively 1/20th of that. I put quotes around "costs" because the spreads have come down from 25 cents per share in the early '90s to 1 cent nowadays. So the average person benefited 24 cents on the spread, and is angry that liquidity providers make 0.1 cents per share? Where was the anger in the early '90s when specialists (a cartel of liquidity providers) were raking it in, making 10+ cents per share? Where is the anger now at Fidelity _losing_ our money in 401ks _and_ charging management fees of 30 to 60 cents per share, annually?
The biggest to benefit from automated traders going away are the Larry Ellisons and other market manipulators who want to buy up companies without "moving the price up." It's all misdirection, trying to convince you and me that we're being hurt. It's the "death tax" all over again. The average person was never affected by estate tax, yet the media convinced us we should be against it, just so some rich jackasses can save money. The same deal is happening now. Rich folks want to buy out the public companies you and I are invested in, cheaply, and stealthily. They don't like automated traders sniffing their actions with pattern matching heuristics and raising the prices (benefiting long-term owners like us).