No, it is not decelerating, it's still growing [0]. Besides, demand from other low-power applications such as IoT will only lead to increased demand for low-power (mobile) chips.
> In 2017, Intel's revenue hit an all-time high, as it did the year before, and its stock is an all time high. This is not a company "fighting for its future."
" ... as Microsoft shows, revenue is a lagging indicator in the technology business." -- pg [1]
Given enough time, all investments will eventually mature. In other words, revenue is about the past -- reaping the rewards from mature (technology) investments. Growth is about the future -- future returns can only come from nascent (technology) investments.
Growth in a new product with lots of potential applications is a much better indicator of a company's potential to continuing earning returns in the future, before that product reaches maturity (and revenue attributable to that product starts to decline). Intel needs a new product category to future-proof its existence.
[0] http://www.asymco.com/2018/02/27/the-number/
[1] http://www.paulgraham.com/ambitious.html
EDIT: as pointed out by several commenters below, I incorrectly internalized your use of "decelerate" to mean "decline" but I'll leave my comment as-is.