You're arguing that companies should implement these measures at the cost of just hiring people? "Companies would actually have to try and make an educated choice about whether or not to hire someone." - Isn't it already a meme that people get 3-6 interviews just to get hired at some places nowadays? and you want to make that worse? Maybe I'm reading that wrong, but employees aren't the big losers in situations where companies are doing layoffs - companies are. If they had more disciplined hiring practices they wouldn't be hired (or, more likely, wages as a whole would be slightly lower because of reduced demand) These kinds of benefits aren't free, and I don't think it's unreasonable that employees bear some responsibility in terms of saving up or whatever if they have to be let go.
All that being said, I'm not against a couple of months of wages/warning, just realize there are costs to this (really, I'm probably arguing most against 3-6 months - that sounds like a really long time to me; It feels like a couple of months should be sufficient in most cases).