In episode 162 of the weekly Hump Day Hangouts by Semantic Mastery, one viewer asked if taking up SEO projects for an HTML-based site in a law and real estate niche would be worth the trouble.
The exact question was:
Hey guys, some industries like law and real estate have these sorta niche-specific site solutions, where the site isn't in WordPress, but in HTML, and only the company they pay for the website can change it. I wouldn't really choose to work with something like this, but someone has approached me with a site like this. Is It worth working with these sites in SEO terms? Or should I stick with WP sites?