Market share is directly linked to sales and they are both directly linked to profits. You can't lose market share without losing sales.
Thats not true at all. Please understand that market share is literally just that. Exactly as it sounds. It's what percentage of the users are using your device/product.
this has no direct link to sales numbers going up or down.
Examples (using made up figures) to show how Market share can go down, while sales increase (similar to what happened in the smart phone industry in the last decade)
Year 1: Company A sells 10m phones, Company B sells 10m phones. Market share is 50%/50%.
Year 2: Company A Sells 15m Phones, Company B sells 20m phones. Market Share is now 42% / 58%
Both companies increased volume of sales. But one company saw decline in market share. This indicates that the market itself is growing.
Further: Market Share also has no direct link to profits. Market share is only about volume and numbers of units. This is completely irrelevant to profit and profit margins, as those are based on individual unit pricing.
More Examples continuing from above:
Company A sells their phones at $650 / device. Costs are $150. They earned $500 profit off Each device.
Year 1 profit would be 5,000
year 2 profit would be 7,500
Company B sells their phones at $650 / device. Costs are $300. They earned $350 profit off each device
Year 1 profit would be 3,000
Year 2 Profit would be 7,000
At the end of the day, Marketshare in a vacuum of data is a completely meaningless number that can only be used for bragging rights. It is important to understand why it is used, but it is being generally overused today just as a statistic in a pissing match.
At the end of the day, why we use market share as a statistic is to help us figure out unit sales, since most of the tech companies don't accurately release that data. But thats really all it can be used for. Unit sales numbers and popularity contests. There is no direct link from MarketShare to profit. and it entirely possible to lose marketshare while increasing sales and profits.
However, in 1st Q 2016 case for apple, Apple did in fact announce a decline of about 10 million units sold.