Not really. The AC transformer was the most efficient way to adapt voltages until very recently. The IGBT and GTO thyristors are the technology that makes something like HVDC affordable today, and they are very modern developments.

Mercury-arc rectifiers (the technology replaced with IGBTs and GTOs) were very large and expensive, and also less efficient (even more so before the 1930s or so) so HVDC only made sense for submarine cables (which have huge capacitive losses). With IGBTs and GTO thyristors it start to become feasible to e.g. do an HVDC line across a continent.

As an example the HVDC inter-island was built using mercury-arc valves (it included a submarine leg), but they have since benn replaced with solid-state devices.

HVDC is also a good to tie two separate grids together; since they will be on different time-bases you can't just directly AC couple them.

No. AC is still far more useful in many key scenarios [1]. However, for long-distance power transmission, lots of money could be saved (and jobs created in doing so) by switching from AC to HVDC.

[1] http://en.wikipedia.org/wiki/High-voltage_direct_current#Dis... (note: some of these are due to AC parts having economies of scale and decades of efficiencies and process that HVDC may not be able to tap into without widescale implementation)