Is it harder to attain enlightenment without a living Buddha? In many Buddhist stories we hear about people attaining enlightenment, stream entry and other blessings. 

It seems like it is much easier to progress in the path when there is a living Buddha around, is that right? Or is it related to the way society was, more religious and devoted?
I guess it is both. On one hand, Buddha new the weaknesses of each individual and was able to recommend what type of meditation that's suitable for him. He new how much each person's five spiritual faculties were developed and provided the right recommendation. This type of knowledge that a Buddha possesses is called indriya-paro-pariya-ñāṇa. I think this is why some monks practice different kinds of meditation techniques alternatively since there's no Buddha to guide them now.
On the other hand, the people during Buddha's time have had perfected paramis onto such an extent that some of them would get enlightened by hearing just one stanza of a sutta. e.g. Bāhiya the merchant, Sariputta thero and Moggallana thero.
In Puggalapannatti of abhidhamma pitaka mentions four types of people,

Ugghatitannu - an individual who encounters a Buddha in person, and
who is capable of attaining the Holy Paths and the Holy Fruits through
the mere hearing of a short concise discourse.
Vipancitannu: an individual who encounters a Buddha in person, but
who is capable of attaining the Paths and the Fruits only when the
short discourse is expounded to him at some length.
Neyya : an individual who needs to study the sermon and the exposition, and then
to practise the provisions contained therein for 7 days to 60 years,
to attain the Paths and the Fruits during this lifetime if he tries
hard with guidance from the right teacher.
Padaparama : an individual who cannot attain the Paths and the Fruits within this
lifetime. can attain release from worldly ills in his next existence
if he dies while practising samatha or vipassana and attains rebirth
either as a human being or a deva within the present Buddha Sasana.

In Buddha's time most of them were type 1,2 and 3. So I guess Bāhiya the merchant, Sariputta thero and Moggallana thero fall under the first category.
These days unfortunately most people fall under third and fourth categories.