Legally, no. Monopolies do not generally need to aid their competitors to the point that they produce viable products. At times, however, monopolies do provide token support to competitors to reduce the risk of anti-trust enforcement. See, for example, Microsoft supporting Apple in the 1990s and Google supporting Mozilla.

Definitionally, companies without viable competitors are monopolies. Microsoft still has a defacto monopoly on PC operating systems as Linux isn't a viable choice for 95%+ of PC users. This market situation is extremely detrimental to consumers but isn't illegal.

Well here then is yet another layer of complication.

Linux has many more features than Windows, gives the user more control, respects privacy better, and is free even, yet consumers choose not to use it.

How far must a company or government go to create competition where the behavior of both the suppliers and consumers indicate otherwise?

Having a monopoly isn’t illegal. Using a monopoly to give you market power in another area is illegal. Windows can have a monopoly perfectly legally, they just can’t use that monopoly to give themselves a monopoly on, say, web browsers.

Google doesn't have to ensure, the government does.