I've just knocked up a quick program to test it and it doesn't look good.

Strike rate about 3.5% and 63% of your cash comes back from 2005 to present day. This is based on SP only, horses at $10 or over. Haven't applied any filters at all and that's all races in Australia including the very small non-tote meetings.
Still, we couldn't expect anything quite that simple to work without some effort I suppose or everyone would be doing it.

KV