Living in very hilly and mountainous areas, 'speed' has never been a big deal to me. It's been about gearing, heart rate and recovery as well as time in the saddle. Every ride is a workout, whether 4mph climbing or 45mph descending.
Next house will be on flatter terrain so I can brag about my speed.
Flatter terrain might also regain me a tandem stoker - grandchild locally is growing up fast. 3 generations on a tandem should be my cycling goal, and justification for an under-used tandem.
edit: re-read my post and thought I should modify (clarify?) my statement.
I have worked for many years to achieve an efficient 'flow'. The 'flow' position is to ride efficiently and conserve energy
so as to ride more miles with less energy. Seems to work for me and my legs.
Besides, this thread needs pics.