ADA compliance isn’t a set-it-and-forget-it thing. Compliance standards must be followed and will evolve just as your website does. There are guidelines all website contributors must know to stay within ADA guidelines. It is generally not burdensome but it does require some web managers to change their workflows. For example, loading images up to your ecommerce site will always need some of that alternative text (alt tags) mentioned above.
The Department of Justice (DOJ) has specifically stated in rulings that websites should be designed so they are accessible to individuals who have vision, hearing, and physical disabilities. There’s a growing body of case law where the DOJ required companies to provide an ADA compliant website and levied hefty penalties when sites failed to measure up.
This guy is right on! You should learn new skills that are critical to your success instead of focusing on your business. Just making a website is easy, making one that is easy for your users to navigate, captures your users' interactions, feed that back to a CRM so you can act on it and setting up automation to handle each one properly so you don't lose the customer is not. (And do not forget, the design of your site is critical to the effectiveness of Google and Microsoft Ads. Without them, no one will ever see your new, beautiful site.)
Your site would need to have a text only option, with all functionality accessible through a keyboard for visitors with mobility issues. Once you make these and other changes to meet ADA guidelines, your site would need to be tested by a website development company familiar with ADA compliance issues to be sure that visitors who use assistive technology such as screen readers are able to access your web content fully.
You may have installed a ramp, increased the width of your door frames, or made other accommodations to ensure that your physical premises are accessible to all. The requirement for equal access used to only apply to physical locations and storefronts, but now the government is actively ensuring that the requirements for ADA accessibility include online properties such as websites and mobile apps.