"The too early is easily fixed"

You can not just stick some new engines to a plane and elongate the body. This needs more investments and certification. Less costly than a new plane but still costs.

"What really doomed it was the proliferation of small airports "

It is hard to predict the future. Just as an example: Many small EU airports may close due to new EU regulation and limited subsidiaries. Many of the small airports create heavy losses that are financed by taxes. This may come to an end. Also, Europe is thinking to revive the TEE trains (Trans Europe Express).

The bottom line: things can change.