I also attribute the general lack of quality of spam to the anti-spam fascists because they have forced anyone who markets legitimate products out of the market. Guess who's left? People selling drugs, sex, drugs for sex, and so forth.
Legitimate businesses have no need of spam. Quality and reputable businesses spend money on normal forms of advertising (radio, TV, newspaper, etc.). Scrupulous businesses don't scrape email addresses from message boards and the don't attempt to bypass filters with numerical spellings and random words and they don't hijack open relays and they don't use fake headers. Any business you'd want to deal with will email you directly, from their own legitimate email addresses, because they want you to know who they are and how to reach them so they can build a profitable, equitable relationship with you.
The reason children don't get porno adverts in the mail is, of course because it's some kind of illegal, but really because real advertising is based on specific, targetted demographics. It costs real money to send one person an advertisment, so real businesses invest in research which tells them who is likely to buy their products so they can maximize advertising effectiveness. It makes better economic sense to send your Geritol ads to old people because that's the sort of people who would by Geritol. Email is essentially free, so illegitimate, fly-by-night businesses and scheisters blanket everyone everywhere with every kind of spam, billions a day for no money at all. The tiny percentage spams responded to make it worth while.
It's not anybody's fault that there is spam, but the people spamming.