The cost is not a big deal. Spending 10's of thousands for a product earning millions is not a big deal.
However enforcement is ridiculous. One of my patents was for a very unique product idea that no other sane person would come up with. One of our distributors announced an exact copy product.
We called in lawyers and they agreed we had an excellent case. At the end of the meeting they said they'd need a million dollar retainer. It wasn't worth it. We checked and couldn't get a better price.
All in all the experience has spoiled me on the idea of ever patenting anything again.
When we met with the lawyers they told us we made a big mistake. We were admitting we knew about the infringement. This sealed the issue of losing the patent. If we had acted ignorant we could have argued later we didn't know about it.
The other benefit is that having a large patent portfolio shows that your company has value to potential buyers.
If the latter, what about selling both patent and product tooling to someone with deep enough pockets to go after the infringer?
Unfortunately yes. The infringer was not big enough to be worth it. However, that meant the patent was then worthless. If you don't enforce a patent you lose it.
Patents only seem to be worth it for large companies and trolls.
P.S. I have always been fascinated by a contrary story. The guy that invented the intermittent window wiper got a patent and the car companies ignored him for a very long time. He sued over and over with no lawyers and eventually got a huge sum of money. Unfortunately he was quite old by then.
Is this a European thing? I've heard of this for trademarks in the US, but never for patents.
There is a general principle in law called estoppel, which means that if you tacitly allow something, you may not later be able to act as though you didn't. With patents that could mean that if you tell Big Yellow Widgets it's fine to make a thing that's clearly your patented Foozablip, but then after a year you say hey, Big Yellow, we just decided you owe us $50 per unit for the patent, estoppel might mean that's not OK. But it wouldn't mean Big Yellow can just keep making them without paying now you've decided on a fee, or that everybody else can join in too. Your patent still applies, it would just be unfair for it to override your previous OK and cost Big Yellow all that money.
That would be surprising to me but I'm just quoting the lawyers. They might have just simplified it.