Playing devil’s advocate here, let’s run with the idea that the slot holder should pay $200k not $100k. Prizemoney for First is $1m so the slot owner would be getting odds of 4/1 or $5. In a hypothetically even race of 10 chances that is no great shakes. If we say that he is only risking $155k because last gets $45k, you could argue he is getting 11/2 or $6.50

BUT this is assuming the slot holder owns the horse. If he is actually splitting with a horse owner the slot owner possibly only stands to get $500k for a $200k outlay – odds of 6/4 or $2.50. Or maybe around $2.80 working on $500k for $177k, assuming the slot splits last money, still terrible when a punter would want $10 odds in an even race. They cannot be in it for the prizemoney alone. The gallops might attract enough race publicity to make this a viable commercial decision but will harness?

In the HRA current scenario of the slot paying $100k pa for a shot at $1m but more likely $500k if splitting with an owner, the odds go back to 4/1 at least
(With HRA kicking in half the prizemoney, even if a non horse owner owned every slot he would only get his money back if he was doing a 50/50 arrangement with the horses' owners)

If the Stallion owners pass the increased levies onto breeders/owners it could be argued that they are putting up $1m and paying for the $1m in total that is going to owners not slot holders – you could say it is a bit like an upfront sustaining payment. I do get that it would be a sustaining payment that all pay without any choice

Would a business want a slot from a profit/loss perspective unless they could get good kickbacks from it - who would that be?!

I can only see the appeal to for a super strong/big owner, being both owner and slot holder they are paying $100k for a shot at $1m or probably more accurately $55k for a shot at $1m - they are good odds.
Win more than once every 18yrs with their own horse and they are ahead