Personally, I don't find "Google is stupid" to be helpful in terms of finding ways to build my business. Google is a force to be reckoned with. It doesn't matter what we think of their product; millions of people like it, so we have to deal with it.
A couple non-Google/non-SEO things that have not been mentioned are catalogs and newsletters. Years ago I had a catalog and it was not profitable. Now I am redoing a catalog of a section of my widgets, because I have found that indeed, there are people who do not have computers of their own yet they still want to buy those widgets. How did they find my biz? Print ads. A lot of them are in rural areas where there is no good internet service (I've lived in them, so I know they are still out there), but others are actual Luddites to some extent. They don't WANT a computer, but they still want to buy things they can't find locally. I find that the mail-in orders I get, though few, are typically for a larger amount than the average online order. I think I could build this if I had a print catalog.
I have started asking repeat customers who mention they are going to conferences in my niche if they would like to have some samples to give to their friends there. They really like the idea. I just started doing this in November. I also enclose business cards in orders now.
I had an email newsletter in the past but dropped it because it was a lot of work. I was trying to make it too much, as usual. I am going to bring it back but change its nature, so that it is a periodic "specific stuff to do with my widgets" thing and throw a coupon in there.
Years ago I used to post in pertinent forums but quit doing it because the general lack of knowledge and posturing was annoying, but I still get clicks from those old forum posts. I do post on Facebook regularly, and not spam. Personal stuff that fits with my products and always include pictures. Then I post about new products with links on my FB biz page, to which my personal page is linked. It is a good place to get feedback on what you have and what you might sell. Some things that people have requested have really surprised me.
Another project I'm working on--ebook based on my site info and info in my niche.
Things I don't do but other ecommerce folks in my niche do: video talks on youtube about info in our niche and classes online--or even off. A couple people do personal teaching by telephone. This would be too much of a time-suck for me, because I used to teach and always over-prepared, but it might work well for others.
I do think retail is inherently risky and has always been. Google is part of that risk. But I also think we are lucky to have online businesses compared to brick-and-mortar. They have to invest way more money than we do.
This thread is good for me because it reminds me to get moving with diversification. It's easy to get sucked into the daily junk of business and forget the long view that might end up saving that biz.