I think analysts upgrades and downgrades of stocks should be put to an end. Some of those upgrades and downgrades can really move a stock and if you look at a stocks history of upgrades and downgrades you can see that they are useless. Biggest abuse can come with options just before an upgrade/downgrade is issued.
How do you think that a firm is supposed to either dump or buy inventory easily? Them upgrading/downgrading is a perfect solution, even though they arent "supposed" to do stuff like that, you know they do.
I don't see how "manipulation" could be a barrier to success. Does it somehow constitute the prevention of you buying or selling? If not, your failure is only a result of your inability to understand what's going on. You don't have to be an insider to know what's going on, you need to develop an awareness of the market. You need to see the market so that you know what happens and why it happens. Untill that day things will be cloudy and random and you'll keep losing money.