Do repetitive, easy-to-build ideas actually generate revenue?

I was browsing BoringCashCow and found yet another seo auto index software, similar to the free wordpress plugin IndexNow. The thing is, that tool has more than $8k/month in revenue with tons of good reviews on twitter.

Like dude, I'm going to build one right now because it's just simple sitemap processing plus using google's indexing api. Of course, I'm still spending time working on my content writing agency so I can't focus too much on saas.

But do those repetitive ideas (also like image resizer) actually bring in revenue?

If so, how to market my product among thousands of others all of which are basically the same thing?