Why wouldn't Zeiss want to profit from more clients?

I would suspect that they have exclusivity deals with ASML?

Edit: It looks like the Carl Zeiss subsidiary that does the semiconductor manufacturing tech is part owned by ASML:

https://en.wikipedia.org/wiki/Carl_Zeiss_SMT

Edit2: Looks like ASML invested a billion Euros into Carl Zeiss SMT:

https://www.asml.com/en/news/press-releases/2016/zeiss-and-a...

It’s like Apple and TSMC. At this scale, both benefit if a large customer helps funding its critical supplier’s technology and infrastructure developments. It’s a symbiotic relationship, both suffer if one has serious issues.

On one hand it’s anti-competitive because it makes it more difficult for the customer’s competitors to use leading edge technologies; on the other those leading edge technologies would be much harder and take longer to develop without the customer’s contribution.

How much did Apple invest in TSMC?

And how is it symbiotic if Zeiss can't take other customers?

> And how is it symbiotic if Zeiss can't take other customers?

Guaranteed revenue that doesn't need sales/marketing to keep going.

> How much did Apple invest in TSMC?

A bunch, like more than a million dollars

It’s a specific part of Zeiss, it’s not like they bet the whole group on it. It’s symbiotic because they help ASML get better machines, which helps ASML get more money, a part of which is funnelled back to its suppliers. In the end it’s a risk assessment: what is the expected value if we get closer to a single partner, compared to trying for a broader market. Also, bear in mind that both sides have to keep the other working: the customer without suppliers is just as dead as the supplier without customers.

So: they depend on each other, and they get more business and make more money by getting closer and have incentives to help the other improve (so it is not an adversarial relationship). Hence, symbiosis.

This part of Zeiss probably wouldn't exist without ASML, and maybe one day when next-gen tech is out tbe exclusivity might be lifted...

The symbiosis is often in legal but specific deals.

And in the imaging and litho world surprising in the level of trust. For example, Sony actually makes a number of sensors for Nikon and other camera makers, despite having often competing products.