Medical equipment is more or less a fixed market unless you are going to sell to developing nations and even then the cost of the machine might very well not be the factor.

Hospitals, clinics and medical staff as well as the infrastructure required to support the machines are your limiting factor.

With portable devices that can hook into a laptop or a tablet it's not much of an issue but still there will be a hard limit for the market and it's considerably lower than you would think.

You also need to understand that the lifespan of some of these machines can be decades so in effect if you make it too cheap you either have to build in planned obsolescence or you'll sell yourself out of the market.

You're assuming the existing customers are price sensitive.

Not necessarily. There is a certain optimal point of price and demand. It's entirely possible that the limited supply due to all the barriers to entry allows even a range of competitors to price their products well above their own costs or the minimal costs in their industry.

It's just not true that multiple competitors have to collude to keep prices well above the perceived minimum costs. Or that collusion is a conscious process, either.