I think that’s the key point: the more browser functionality you take over, the more of a resource commitment you’re making to support that extra code. If you’re Google or Spotify, you can easily afford that and in the latter case you have a strong argument for necessity because there’s no way to keep the music playing across page-loads.

The key part is making sure that you’re taking on an appropriate level of work for your team and site. A local restaurant website should probably prioritize loading quickly since most people are looking for fast answers and the owner doesn’t want to pay to maintain a heavy tool chain which requires frequent maintenance.