Places with teams that have more history will have more support in the lean years since there's generations of people raised on the team. I don't think that's a question. If we're basing team worthiness on fan support, it makes a lot of sense to handicap teams based on how long they've been around. For example, the kids that would have been raised on Coyotes hockey are only now coming to an age where they can afford tickets. I'm not saying new teams get a free pass on crappy attendance, just that if we're getting down to it I see a lot more negative in a team like the Blackhawks suffering like they did than a team like Florida suffering. To take it to the NFL, the Chargers situation is worse than the Jaguars recent situation. The current Pistons situation is worse than the current Memphis situation. However, it all comes down to the operations of the team, IMO. If a team is winning, people will come unless there's something like the Coyotes where the team is just a mess and also winning. In other words, I think it's a lot more complicated than saying "they don't show up, they suck and don't deserve it."
The fact that places that have had hockey teams for 50 years or more support hockey more than places that have had hockey teams for 30 years or less should be the least surprising thing in the world.
When it comes to dilution of talent, that seems like something that should be fairly easily debunked just looking at population growth and the growth of international (non-NA) talent in the league. While the talent will obviously lag 18-24 years behind population growth, the growth of North American (minus Mexico) and European population has kept pace with the addition of new teams since 21 team good ol' days. In 1979, there was one team per 11.85 million North Americans (249 million combined US and Canadian population/21 teams.) Today, there's 11.67 million North Americans per team with 31 teams (11.31 with Seattle added and no additional growth.) Add the Europeans coming over to the league and the talent dilution argument seems ridiculous.
This isn't even touching on the whole stand up versus butterfly/profly thing and all the other changes that have been made that have impacted play since the good ol' days.
The Golden Knights thing could go either way, and the way someone sees it is likely to include their bias based on what they feel is happening with the league. The NHL is either so weak and lacking so much talent that an expansion team can make it to the Stanley Cup Final or the league has so much talent that expendable pieces and third liners can make it to the Stanley Cup Final if they're all given a shot to play. I subscribe to the latter more than the former, and I feel like that viewpoint is a little more supported by evidence than the former.