Estimate how many people are searching for property at a given time, how many of them would use your view-focused site (a tiny fraction), how many of them would find something through it and hence give you income (probably referral bonus from whatever big property listers you're partnering with).

Now weigh that against the cost of creating/running a site, and digging out the properties with a view.

I've not done this rigorously at all. But in the site I worked on, I suspect people filtering by facets similar to "has a view" were, optimistically, about 1% of our engaged audience. Conversion rates were like 5%. So that was probably a few tens of people per day (we had a fairly big audience!)

If you monetise by referral bonuses, you'll probably get tens of dollars per referral. So at most ~100USD per day.

Now consider the costs of setting up and running such a site. Remember that we were a global property search engine -- to get that thousands-strong audience, we were running all over the world.

IMO it just doesn't add up.

You can always prove me wrong! One way might be to focus on high-end clients, and somehow make more money from them... larger referral bonuses, for example, or having the clients pay you to find them properties with a good view.

But yeah, I remain sceptical.