My understanding is that the 80/20 rule applied only to the right to purchase seating at home athletic contests.
Back when the 80/20 rule was in force, we periodically discussed that, to evaluate the fair market value of the right to purchase other sorts of seating, we were back in the territory of having to come up with a good-faith assessment of the value of such rights (as challenging as that might be). The 80/20 rule just applied a special rule for determining the fair market value in that one case, the right to purchase tickets for seating at home athletic event, and it set the value of the benefit at 20% of the amount of the associated contribution.
When the deductibility of the right to purchase seating at home athletic contests under the 80/20 rule was eliminated, the language was just that the deductibility under that section was eliminated, specifically. Again, there is no impact on any other types of rights to purchase seating not described in that section.
Here's the language:
(l) Treatment of certain amounts paid to or for the benefit of institutions of higher education
(1) In general
No deduction shall be allowed under this section for any amount described in paragraph (2).
(2) Amount described
For purposes of paragraph (1), an amount is described in this paragraph if-
(A) the amount is paid by the taxpayer to or for the benefit of an educational organization-
(i) which is described in subsection (b)(1)(A)(ii), and
(ii) which is an institution of higher education (as defined in section 3304(f)), and
(B) the taxpayer receives (directly or indirectly) as a result of paying such amount the right to purchase tickets for seating at an athletic event in an athletic stadium of such institution.
If any portion of a payment is for the purchase of such tickets, such portion and the remaining portion (if any) of such payment shall be treated as separate amounts for purposes of this subsection.
My US$0.02 worth; the usual disclaimers apply.