I think you're ignoring what competition means.
I'm not saying all these tight ends are going into the HoF, it's quite the opposite.
Gonzalez will go in. Gates will go in before Witten, and Witten will have trouble because then he will be on the outside looking in. Only 8 tight ends have gone into the HoF in the modern era. They aren't about to put 4 or 5 in, and guys like Graham and Gronkowski will end up going in before Witten. They will easily eclipse his numbers by the time he is eligible.
I understand what competition means. I don't see the competition at the tight end position. You start listing guys like Greg Olsen and Julius Thomas and neither provide any competition to Witten or Gates.
Just because something was done in the past means it will continue to be the same in the future. The committee doesn't have to continue to ignore the tight end position. In the past there were generally only a couple of tight ends of each generation that were HoF caliber. It really isn't different today. Gonazles has 6 years on Gates/Witten and really could be considered a separate generation. Gates and Witten will be their generation's representatives. Gronk and Graham might be their generation's top tight ends, but it may be too early to speculate they are HoF bound.
The HoF committee won't have to put 4 or 5 in at the same time. Gonzales is already retired and will inducted in 5 years. Gates will retire soon and will get inducted quickly as well.
Gronk and Graham will not easily eclipse the numbers Witten has accumulated in his career. Gronk and Graham have benefited by playing with Brady and Brees, respectively. How long is either situation going to last? Witten produced with Bledsoe and Testafreakinverde. Gronk has serious health issues.
As I said, due to health Gronk has probably 3 years left. Maybe 5 tops. He isn't going to produce the monster 90 reception years anymore. He has had significant back issues since college. People get concerned with Romo and his back problems, but Gronk has had more back problems for a longer period of time. Gronk also party's hard. I don't think he plays long enough and puts up the raw totals to get into the HoF. If Gronk does retire in the next 3 to 5 years his totals will be so far behind Witten except for TDs that he won't go into the HoF much less get in before Witten.
Or let's assume Gronk is able to stay healthy and play 10 more seasons. Witten will be retired and eligible for the HoF before Gronk even retires. Why would Witten have to wait in that scenario?
Jimmy Graham could possibly play 10 more years as well, which means Witten could be in the HoF before Graham even retires. Why would Witten have to wait on Graham? And that is assuming Graham does play another 10 years and is very productive those 10 years. Graham will be 28 in November.
It is difficult chasing the guy in front of you. Tony Gonzalez has put up some incredible totals over a very long career. Most tight ends don't play and certainly don't produce much after the age of 32. I think Witten will fall short of catching Gonzalez. No shame in that because it is a substantial difference in what Tony accumulated and what Jason accumulated. The same applies to those younger guys chasing Witten. You ignore just how many more receptions and years already put into the league that Witten has on these young guys. I doubt any of these young tight ends get close at all to Witten's reception totals. Again I fail to see the ton of competition