No there are many different manufacturers including SRAM which now owns Hammerhead but Shimano does have about 70% of the marketshare.

Many is an overstatement. You only really have SRAM and Campagnolo that are making decent groupsets and of the two, SRAM is the only one that makes MTB groupsets. MicroShift is there at the lower end and is probably best avoided unless it solves a specific problem you have. SunTour isn't doing groupsets anymore. You don't want to bother with the Chinese knockoffs of Shimano.

oic. SRAM was not as common here in Europe when I first started bicycletouring though. But I can see they are present on some Swedish webshops now though.

There are plenty of manufacturers making gears. (Cassettes and chainsets) For example mine are by their main competitor: SRAM

No, SRAM and (to a lesser extent) Campagnolo are two other fierce competitors.

All three are going to see their profits being swallowed up by competitors like MicroShift on the low end side of things. Making 9 or 10 speed groupsets is not really rocket science anymore. People (like me) that don't want electronic shifting will be flocking to them. All this broken interoperability and forced obsolescence from electronic parts is just too much unless you really need to cosplay as your favorite Euro Pro Tour rider on your lunch breaks.