Like you, I am still finding a ton of bad SEO, even from "reputable" companies who have been around a long time and talk the talk. It is amazing just how bad some of their work is - or how non-existent it is in some cases.
I have also worked directly with a few well-known internet marketing companies on larger projects only to find out that they are doing some pretty shady things, or not doing what they say they will.
My current pet peeve is large web design & development companies who sell SEO as an add on to their trusting dev clients. Then they do absolutely nothing, other than maybe 5 minutes of keyword suggestions. The developer will launch a site full of severe content duplication issues, then charge a few thousand a month for an SEO package and take 3 months to fix the issues the dev team created, and call a meeting with the whole team and the client to talk about this great new discovery they have just made: rel="canonical".
That is like buying a brand new car, then paying the dealer's mechanic a hefty fee to make sure the manufacturer designed and assembled the car properly.
We can try to educate clients as much as possible, but many will still be tempted when someone comes along saying "oh we have a totally new Google-friendly thing we do called a link wheel. 100% white hat and Panda/Penguin safe. Only $129!" I am sometimes jaded enough to think the people who fall for such scams because they want something for nothing get what they deserve... yet I still find myself trying to help them anyway. It is the high profile, seemingly legit companies who are actually not much better that really bug me.
**But I am optimistic. **
All of Google's webspam efforts and the growth of communities like this one are helping to make it harder for scammers and just plain incompetent SEOs to keep doing what they do.
The good news is word of mouth does work. Kind of like how we tell clients to provide great content and user experience and the links and rankings will follow; when we provide awesome, effective and honest service - the referrals will come. Being truly helpful in communities like this, on social media, forums or anywhere else also works to show your knowledge and spread the truth about real SEO and dispel misconceptions. Even getting into an argument or calling BS on someone when they are spouting nonsense can actually attract new clients. There are plenty of smart website owners who are sick of all the bull and are happy to stumble upon a good rant, apparently.
There will always be scammers and cheap link building services - just like there will be some clients who never learn that you get what you pay for. But it does seem to be getting better. Fear of Pandas & Penguins seems to help some.