mentions a critical point:
...audience demographics and intent play a big role...
No one size fits all especially on the web. Every referrer sending traffic has a to some degree different demographic, this is true between SEs as well as SM platforms and individual sites. And they tend to shift over time.
For those of you relying on a primary referrer, i.e. Google, remember that platforms (not just SEs) have been creating filter bubbles via personalisation. And that it works both ways: sites are categorised as well as visitors. Increasingly search is determined to match up round visitors with round sites, oval with oval, square with square, etc. The narrower less inclusive/expansive your site/page the smaller your bubble of available referred visitors. So increasingly one gets perfectly matched (for some definition of matched) visitors or those or whom they couldn't find a match.
And that is without bringing visitor intent into play.
And as mobile user uptake increases and ad spend increasingly moves to mobile intent is increasing other...
So, a matched visitor is likely to convert as you'd like/expect but there are probably far fewer.
How do your pages receive and guide those whose intent/interest differs somewhat to significantly from the landing page? These are almost certainly an increasing majority.
If your site is content targeting large screen user intent simply made mobile 'friendly' you are likely mistargeting increasing numbers of visitors' intent.
Getting context right is critical going forward.
Things, including search engines and ad networks and advertisers and visitors and... behaviour, change. If that change negatively impacts your business it needs adapt in some way(s) or must absorb the loss. Doing nothing is easy, it may not be conducive to survival but it certainly is easy.
I'd like to give concrete by the numbers solutions but no two sites or business models are the same. And generic advice is as likely to be counterproductive as productive.
What is your product/service?
What is your unique selling/value point(s)?
Have enterprise sites come into competition?
Why your site and not one or another of your competitors?
Is your niche attracting competitors?
How are your referrers changing that affects the traffic they send?
Where is your existing audience, market segment?
Where are your prospective audiences, market segments?
Does your business model need to change?
---how does your revenue model need to adapt?
---how does your marketing model need to change?
Etc. et al ad nauseum.
As I get older I increasing detest change while being better at recognising it. So I get grumpier while adapting. Just in case you were wondering where old grumps come from. Bah Humbug.
p.s. illegitimi non carborundum