I find it interesting that they are considering applications from last year only.
For me last year was interesting. Prior to 2020, for PGP, income for previous 3 years (if you apply on year x then income for years x-1, x-2, x-3) were counted. In 2020, IRCC for the first time, allowed potential sponsors to count the income that they are expecting to earn in future and have not earned yet: interest was submitted on October 2020 with a condition that one can earn enough that is needed LICO for the year 2020. This (not sure how pragmatic it is) allowed some of us to work and/or earn more on Oct, Nov and Dec to hit the target LICP, again I am not sure if this assumption is practical.
Now from this year, they have restored the old trend (I assume). Such that if you get a chance to apply/show interest on 2021 (x), you need to earn enough on 2020 (x-1), 2019 (x-2) and 2018 (x-3). If we were to assume that IRCC have restored the old trend, basically only those people who were eligible for PGP2020 would be eligible now for PGP2021. May be this time those who missed to submit their interest, despite the fact they were eligible and were not able to manage to submit the interest even though system was open for more than 2 weeks (if I am not mistaken), would have been included.