Apple is just getting started with Apple Silicon

pulseimages said:
As an owner of a 2019 MBP 16” Intel do I need to worry about Apple not supporting it anytime soon? 

It depends on the country (and in the US, the state) in which you live, but the generic Apple policy in the US is that machines move to "Vintage" status (no support from or repair in App Stores or at Apple Authorized repair outfits unless they haven to have parts in stock) five years after Apple stopped selling that particular model (so roughly October 2026 for your model). At seven years, machines are classed "Obsolete," and no hardware service is available from Apple.

All that said, Apple has stated that it's making spare parts and repair hardware available to consumers and repair shops (e.g. the recent iPhone parts and hardware made available in the last several months), so there may still be repair outfits that stock the parts for a year or two after the seven-year deadline.