@TheWanderingMist has a really good point here about "8 people kicking around in a random field"
Older titles are always different. An actually good real life example that I've recently seen debated comes to mind. Not sure how many people here follow tennis, so I'll quickly explain something in one or two sentences here just to give you the context, without wasting too much of your time.
Context:
The four biggest tournaments each year (Australian Open, French Open, Wimbledon, U.S. Open) are called majors and are the only modern tournaments with 128 participants (7 rounds). Serena Williams has won 23 majors, while the all-time record is Margaret Court who won 24.
Recent controversy:
After coming back from maternity leave, Serena has lost 4 straight major finals, and some Serena fans have started to claim that "she already has the record" because if you look at several of Margaret Court's earliest titles decades and decades ago, there weren't 128 players, some of them had as few as 48 players with weird formats like first-round byes, etc.
The facts:
All of Margaret Court's 24 majors are real titles. Tournaments evolve over time and obviously the earliest iterations won't look anything like the modern iteration because the tournament was still a fletchling tournament in its earliest stages, still growing into what it became today. That doesn't delete those earliest titles from existence. If we did, then would we have to delete all titles every single time there's a rule change?
The point:
Ash has won the first Alola League, which probably looks nothing like what the Alola League will look like 100 years, if not even 20 years, from now. Yet, it is still a league that he has won. That can't be debated.
(p.s. on the tennis thing, I am a huge tennis fan so if you want to discuss the stuff I just mentioned, or other stuff, write on my wall or PM me rather than continuing it here)
actually it made no sense considering that Red only defeated ONE of Blue's Pokémon.