if we start seeing issues with block rewards being too low to maintain acceptable security, we're going to have multiple solutions being implemented for it, and definitely a hard fork to indefinitely maintain some degree of block subsidy
if we failed to first try increasing block demand with advanced transaction support, it would seem like we were just throwing money and growth away to support one narrative (simplicty of function), while destroying another (finite supply)
if stuff like covenant support and mweb gets us higher fees, with stuff like on-chain mixing protocols, vaults, and higher utility, it might be more than enough to sustain bitcoin on fees alone forever