Taproot upgrade is the biggest upgrade in four years after Bitcoin’s network saw segregated Witness, or “SegWit,” upgrade in July 2017.
A Coindesk report pointed out that, so far, only a little more than half of known Bitcoin nodes are signaling support for the upgrade.
Developers, who are looking for ways to make use of current space more efficiently, can’t simply increase this limit without affecting on Bitcoin’s decentralization.