Yes. Never been easier to build a browser than today with great open source engines. Writing an engine from scratch is the hard part. Extremely labour-intensive to build and then maintain. People usually conflate both.

edit: clarify

Browser = browser engine. Without it it's just a collection of extensions.

This is oversimplifying a lot. Two browsers can support the same extension system and still be quite different (e.g., Firefox vs. Orion).