What evidence do you have that people borrow against assets as some tax avoidance strategy? What are the details of this brilliant, often repeated plan? In particular, where do you get interest rates that are low enough to make it worth it to avoid capital gains even with an asset that's grown 100x over its cost basis (and are you accounting for reinvestment of income like dividends that can't indefinitely defer taxes, creating regular tax lots with higher basis that you could sell first)? e.g. are they getting better interest than SOFR somewhere?
The framing was slightly glib, and you're correct that current rates impacts the equation, but there has been real damage caused by how extremely attractive this strategy has been over the past decade. We sitting on an unprecedented peace time deficit due to a failure to properly tax an economy that has been massively prosperous during this same period. This strategy is small part of it, but it is a real part.