It's not a matter of access by virtue of light level, it's the fact that they have these strikes because it's part of the original game they have bought. The only way for these strikes to come back would be to include them in Destiny2 albeit a little different. If Bungie shuts out the players that still play because they didn't buy TTK, they would lose face and their player numbers will suffer greatly, if not already.

Your point is moot. Omnigul is in the year two nightfall list and that's a year one strike.