No doubt it hurts small business the worst, but I'd not agree with the notion that all big businesses net gain from this. Lawyer time isn't cheap, and the bigger you are, the more attention you gather. And of course, patent trolls optimize to use the most lawyer time possible, to make it less efficient to defend (sometimes, it legitimately isn't worth it.)
Basically abolishing patents would definitely receive pushback from bigger and even smaller companies, but improving case law to be more reasonable really wouldn't.
If you're big enough you have teams of lawyers on staff. It costs you literally nothing extra. If you're not big enough to have staff lawyers you're not big. Small businesses are pretty much everyone else. You can't polish a turd, and this system as well as the copyright system are a giant turd that's antithetical to the original intent of the law.
The lawyers they have on staff wouldn't otherwise be shooting pool and drinking beer, they'd be doing useful things for the company. There's a big (opportunity) cost.
Plus lawyers are not all interchangeable, just because you have people who know employment law or how to M&A didn't mean they are good at fighting patents on court. AFAIK they're usually externally firms, not in-house lawyers
Basically abolishing patents would definitely receive pushback from bigger and even smaller companies, but improving case law to be more reasonable really wouldn't.