"WordPress is outdated." "React is overcomplicated for a simple site." I hear both regularly. Both are wrong - or right, depending on the situation.
As someone who primarily works in React and Next.js, I could say custom is always better. But I'd be lying.
WordPress makes sense when...
The client wants to change content frequently themselves. Budget is limited and the site is simple. Speed to market matters. The team already knows WordPress.
React / custom makes sense when...
You need specific functionality. Performance is critical. Design must be completely unique. You plan to grow the site into an application.
Where people go wrong
"WordPress is free, why pay a developer?" - WordPress is free. A good WordPress site isn't.
"React means a better site" - Not automatically.
"The developer pushes what they know" - A real problem. A good developer asks what you need, then recommends a tool.
Real example
Restaurant client - menu, gallery, contact, reservations. WordPress? Fine solution.
SaaS startup - user panel, subscriptions, API, admin. WordPress makes no sense.
Same developer, two different answers. That's the point.
Don't ask "React or WordPress." Ask what the site needs to do in a year, who updates content, what's the budget, and whether you need something templates can't do.