It seems that "in the olden times", the times of the Mishkan... in its several incarnations, and the First Beit HaMikdash and the second Beit HaMikdash, that the Jewish people often let spiritual and holy things take place in the Mikdash and somehow failed to internalize the experiences and lessons. The Tanach tells us of people bringing hollow, empty korbanot and behaving in terrible ways. How could people sacrifice to G-d on forbidden Bamot? Did they not see the utter contradiction in their behavior?
We really shouldn't be judging generations of old. we have enough to concentrate on our own behavior. On the other hand, we have to learn from mistakes of the past. Otherwise, how will we be able to improve ourselves as individuals and as a community. How will we hasten the Geula. How will we merit the Third and Eternal Beit HaMikdash.
During the tenures of the Mikdash, people always davened. Prayer was not created as a substitute for Temple service. But it has served that function for a very long time. We have been without a Mikdash more than 550 years longer than the time from the building of the Mishkan until the destruction of the second Beit HaMikdash. We have to have learned many important things during that time. We should have learned how to make and use and properly respect the Mikdash Me'at, our shuls. We should have learned how to serve G-d with all our heart - to daven on the level of kohanim doing their Avoda. We had to have learned how to build a Mishkan in our hearts and offer our very Nefashot in complete sacrifice to HaShem.
These things we should have learned during the absence of a Mikdash, not to replace it, but rather to be able to survive and thrive as Jews during its absence... AND to reach even higher heights of Kedusha when it will be restored to us. Are we ready for that challenge?