The traditional Inuit/Eskimo economy and lifestyle was coastal. If they moved inland into Canada, they would be in competition with the indigenous people already there. In many ways, inhospitable is hospitable - at least there is less or even no competition from others. In either case, whether due to other people or permanent ice cover, the length of coastline is more important than the actual land area. That said, Canada and Alaska do offer more coastal area for Inuit/Eskimo settlement; by a crude eyeball estimate, perhaps about 2.5 to 3 times as much coast in Canada, and about 1.5 times as much in Alaska.

How do the populations compare? The US Inuit population is about 54,000, of who about 48,000 live in Alaska. The Canadian Inuit population is about 59,000, of whom about 27,000 live in Inuit-dominated Nunavut. Russia has an Inuit population of about 2,000, and an Eskimo population of about 18,000 (if one include the 16,000 non-Inuit Chukchi people, as traditionally done). The Danish population of Inuit is about 58,000, or whom about 51,000 live in Greenland. Thus, while the majority live outside Greenland, the Greenland Inuit population is higher than one would expect from the Canadian, US, and Russian populations.

However, there was a catastrophic population drop in the 18th and 19th centuries due to newly-introduced diseases such as smallpox, tuberculosis, and smallpox. In Canada and Alaska, the Arctic population might have fallen by 90%. No reliable population data is available for Greenland before the 18th century; a contemporary Western estimate of about 30,000 is often regarded as unrealistically high. Whatever the population of Greenland was in 1700, it appears to have dropped to a low of 6,000 due to smallpox by the mid-18th century. The lower estimates of the pre-epidemic population are about 8,000, which would make this a relatively mild smallpox epidemic compared to the catastrophes suffered by other indigenous populations without prior exposure to smallpox. Certainly, compared with other indigenous peoples, a drop in population from 30,000 to 6,000 is credible. The Canadian Inuit population appears to have dropped to as low as 2,000 in the mid-19th century.

Modern Inuit populations have grown greatly from those low levels. Recovery of the Canadian Inuit population was slowed by ongoing disease (which also slowed population growth in Greenland), and by overhunting in the Arctic reducing the availability of traditional foods. With reduction in the impact of disease, the Inuit population of Greenland grew from about 10,000 to 50,000 during the 20th century, with much slower growth in the 21st century. The population in Canada also grew, also reaching about 50,000 at the end of the 20th century. Unlike Greenland, the Canadian Inuit population has continued to grow rapidly in the 21st century, at about 20% per decade. US Inuit population growth has also been rapid in the 21st century, about 15% per decade.

The modern populations are largely the result of recovery from the demographic catastrophes of the 18th and 19th centuries, and don't reflect the length of coastline suited to the traditional Inuit lifestyle. The relatively high Greenland Inuit population appears to be the result of a less catastrophic fall in population.

References:

Modern populations and recent (21st century) growth: T. Kue Young & Peter Bjerregaard (2019), "Towards estimating the indigenous population in circumpolar regions", International Journal of Circumpolar Health 78(1), 1653749, https://doi.org/10.1080/22423982.2019.1653749

Demographic change in Greenland: Marquardt, O. (2002), "Greenland’s demography, 1700-2000: The interplay of economic activities and religion", Études/Inuit/Studies 26(2), 47-69, https://doi.org/10.7202/007645ar

A convenient online map showing areas traditionally settled by Inuit: https://www.arcticcentre.org/EN/arcticregion/Arctic-Indigenous-Peoples/Demography