Sell them on you building and maintain their website while they do what they do best, run their business. You can handle the design, setup, adding content, updating content adding new content, handling updates and monitoring uptime.
Expand to offer custom web applications (rails/laravel) most businesses can use something custom for their business/data, a simple stripe ecomm setup, surveys, CRM, allow customers to customize and/or price services/products, email/sms alerts for customers, appointment reminders, there are lots of things you could do with businesses and custom web apps.
Talk to them about their business, what are their pain points, how can you solve them with technology, website, forms, web app. Three is still lots of opportunity out there.
I think small companies that doesn't want an astonishing, unique website has gone to these, as in short term it's cheaper solution.
Most designers I know are no longer searching for I-need-simple-web-design but for clients that need complete design project/guidelines (that includes public facing website and internal admin panel etc.)
Just because you have access to good Drag&Drop builders does not mean web design or web design programmers (CSS etc) are out of business.