At least in the software and IT business it seems (it is clear to me) the other way around. Patents are protecting the incumbents and big companies, who can afford legal experts to defend themselves.
- can not afford to patent everything they do - can not afford to find potential infringing companies - can not afford patent lawsuits
Even when they patent, and even when they know, that some other company infringes their patent, they just are not able to take the risk of patent lawsuits. In the case of a big other company it also can be the same as suicide. There is an anecdote, that one big company (everybody knows) send their patent lawyers to a small company, saying, they are infringing their patent X. The small company proved to the lawyers, they did not. But those hard-boiled lawyers just said: Look, we have X-thousand patents. We will find many others, you infringe and sue you, unless you pay us now for this patent! They paid, of course!
The patent system has become like highwaymen -- many see the big money without effort -- and it is. Those that are robbed, oftentimes are the real creative persons. And so, the patent system just has become the opposite to what it pretends to be. And of course, patent-attorneys, lawyers and even politicians defend a corrupted system, because they benefit from it.
Best example is Bill Gates: In his early time he stated, that patents on software would harm the software industry. Today he is one of the biggest proponent of the system, since his company today is big and he things it would profit from it. But in the end, even for M$, I doubt.
It's the huge tech companies which have amassed and keeps on amassing broad software patents which is the real problem.
The only reason we are actually seeing some legal action being taken against 'patent trolls' (i.e non-practicing entities) is because they are a nuisance to said huge tech companies.
Meanwhile these tech giants will use software patents to stifle / destroy competition instead of competing in the open market, you don't need to look any further than Microsoft and Apple's patent suit against Google which they are doing through third-party patents they bought specifically for that purpose, to stifle a competitor with which they can't compete on the open market through the value of their products.
Now Google is a massive company themselves and has the funds to atleast mount a proper defence (not that it will matter in the first instance as Microsoft and Apple chose East Texas as it's venue), but if you are a startup you have zero chance against these tech giants when they come knocking.
They can afford to drag this through court for ages, you most likely can't, and even if you could and if you won, they could most likely simply choose another patent from their arsenal and go after you again.
There where times, when getting a patent was really difficult, also for bigger companies. But today, every little nuisance can be patented (e.g. 1-click), just formulate it right and bring old things into new contexts to convince patent-officers (e.g. round edges). Of course patent-officers have their own advantages today, when more patents are granted ... what a mess!
I do not speak for the (small) company I work for in any official capacity, so I will not go into the details. But we have quite a few patents, and they have been useful. There is considerable risk in coming up with a new idea and launching it in the market; a risk that a small company cannot afford to get wrong too many times. There is the risk of failure, and then just the opportunity cost of having your small team work on project A vs project B.
If our work was unprotected then larger companies could just sit and watch the small companies try, and then swoop in and take over the market if the idea is valid and the market is there. Recall that Microsoft received the "evil" moniker (which I don't really agree with, btw) in part because how often they did exactly this.
Sure, there are all kinds of injustices and inequalities in the system; I do not argue the system is perfect, nor do I suggest that I have any idea how to improve the system. There is value, however, in rewarding a company that takes risks and generates new ideas. Perhaps that value is overshadowed by the value destruction by patent trolls, I don't know (would have to see the numbers). But it is a value.
But could you actually take on a large company and win? Or is it just a theoretical possibility?
Do you have the means, or it's only luck?
In fact there is a much worse fate that having your precious idea "stolen": when you are the one sued, because someone (small troll or big Sauron company) has a patent on doing square roots on the internets.
If that were true we wouldn't have any patent system at all.