Remember, you can check the full document Paschale Solemnitatis on this site, among many on the internet.
100. The celebration of Easter is prolonged throughout the Easter season. The fifty days from Easter Sunday to Pentecost Sunday are celebrated as one feast day, the “great Sunday”. (Cf. General Norms for the Liturgical Year and the Calendar 22)
Fifty are obviously more and greater than eight. In some quarters, I do read of the lament of the loss of the Pentecost Octave, but the last day of Easter actually gets a promotion with being the crown and conclusion of one “great Sunday.”
And we know that Sundays of Easter rank above any possible liturgical observance. Except Ascension when it is transferred:
101. The Sundays of this season are regarded as Sundays of Easter, and so termed, and they have precedence over all feasts of the Lord and over all solemnities. Solemnities that fall on one of these Sundays are anticipated on the Saturday. (Cf. Ibidem 5, 23) Celebrations in honor of the Blessed Virgin Mary or the saints which fall during the week, may not be transferred to one of these Sundays. (Cf. Ibidem, 58)
Comments?
Catholic Sensibility 
The Pentecost Octave was unusual in a few respects. It contained the summer Ember Days and, as best I can tell, the Ember Days preceded the development of the Pentecost Octave. The Ember Days were placed outside of Paschaltide because they were penitential days (though the Rogation Days before Ascension Day were also penitential, as were the Vigils of Ascension and Pentecost – vigils always being penitential days, traditionally). So, when the Octave developed, the Ember Days had certain penitential elements transformed – red instead of violet, the Alleluia retained, et cet., and the fasting/absintence requirements normally associated with them were at some point deferred or commuted in some ways.
In many countries, Pentecost Monday (and, in earlier times, Tuesday), like Easter Monday (and ditto Tuesday) is a public holiday. (In Germany, it may still a holyday of obligation (Pfingstmontag), a residue of preconciliar days of precept.)
In the current missal, on ferias of the week following Pentecost that don’t have obligatory memorials/feasts, a celebrant could choose to celebrate the Votive Mass of the Holy Spirit.
PS: Ascension Day is Father’s Day in Germany…
“In the current missal, on ferias of the week following Pentecost that don’t have obligatory memorials/feasts, a celebrant could choose to celebrate the Votive Mass of the Holy Spirit.” And indeed I do!