Basically, like someone else in this thread already said, SEO is best if you are not doing it actively, but when you are creating stuff that really benefits users, readers, etc…
Once you get to the point where you're simply trying to eke out a handful more visits a month. There are some fundamentals that absolutely need to be in order that can have a massive impact on your success. Stick to the 80/20 rule and only do the 20.
I once worked with a small company where essentially 100% of their PPC spend was wasted. Not half wasted, not mostly wasted, but completely wasted.
The marketing manager was determined to spend her budget though, for fear of losing it, so month after month she tinkered with keywords, rewrote ad copy, and the ads ran and ran, sometimes people clicked, views were tracked, but there were no conversions.
You're thinking maybe the conversion tracking was broken? It wasn't.
A handful of people searched for the company's name, and they did convert. The company ranked #1 across all search engines for its own name, so why they were running PPC ads on their name was somewhat of a mystery. At least it proved the PPC tracking was working... and proved the PPC campaigns were an utter failure :/
Watching $thousands being tossed away like that was quite sad. In one fractious meeting I suggested that it might be more effective to stop the ads, and stand on a busy street corner handing out the cash and asking passers-by to buy the product. It couldn't have been any less effective...
Because that's how Google works. If you don't, your competitor might do, and then your organic first place won't actually show first.
...but it's such a terrible industry, that needs major disruption.
Most of the big travel sites have in-house SEO teams, who do A/B experiments, have entire frameworks for quickly rolling out changes to things like page titles, subheadings etc. across an entire site - and the proof there is in the pudding, search for "Hotels in XYZ" and they'll be on the front page.
But you're talking about a team of people, most on 6 figure salaries working full time, because the ROAS is there.
If that were true. Google's results would be better.