RamPage01, yes you can upgrade between the cabinet and the home, but it is the shared fibre on the other side of the cabinet that is not upgradable and would need replacing from scratch to obtain the full benefits of an upgrade to FTTH.
The fibre from the exchange to the node is always going to be shared. The fibre from the exchange will connect to a switch in the node, from there to Field Outlets (homes).
The only pitfall I can see in Street Cabinets is perhaps cooling, but I have seen plenty with very limited cooling and they work ok and have done so for years.
