Chaser convergence is often subjective. It was cited that Tipton, OK (5/16/15) was among the worst convergence heading east from Tipton, yet I was up close and personal with the tornado, bailed east last minute and encountered very little traffic/convergence. Either the backup was short-lived or it was relatively isolated to a specific road. That sort of thing happens a lot, especially in vicinity of a tornadic supercell.
The difference with Tulia/Vigo Park is that, the combination of traffic/congestion/convergence/reckless driving behavior was easily the worst that I have
personally experienced in my chase career thus far, which spans nearly 300 storm chase days. Convergence along a road is one thing and many of us have seen this plenty of times. I can cite Pilger and Dodge City as two examples of dozens (if not hundreds) of vehicles backed up along one stretch of road, but in those cases, in my experience, the backup did not affect the chase too much and I didn't personally have issues with other drivers. Near Vigo Park, I had multiple close calls with other chasers who were driving recklessly. Subjectively, the reckless behavior was the worst that I had witnessed during any one storm chase event and it was echoed by others across social media and on Stormtrack.
Yes, there were many factors leading to a "perfect storm." A moderate risk in May in Texas with one storm focused in an area with a poor road network and limited cell service. Most dirt roads were ruled out due to antecedent rain. Many chasers were punching south last minute due to earlier storms to the north. You had a situation with a large number of chasers arriving at the same point around the same time. Luckily the storm was not tornadic at this point, as it could have turned into an El Reno or worse situation. As it was, there was a borderline panic from what I was seeing on the roads, meaning chasers pulling out into oncoming traffic, parking in the middle of the road, not using turn signals, swerving, driving at erratic speeds, etc.
Chaser convergence is getting worse. This can't be argued. More chasers are out in the field and this isn't a bad thing. It's an issue when you have inexperienced people, plus locals, plus your average Joe who has little to know education on how severe weather works. More people than ever before are getting closer, whether it's due to following other chasers (either via social media or literally following on the road) and/or apps like RadarScope allowing chasers to get close to the mesocyclone (or other red dots).
Each experience is personal.
@Dan Robinson often cites not having many issues with convergence. If you avoid main roads, don't get dangerously close (like directly under an HP mesocyclone with little to no visibility) and always plan a few steps ahead, then you'll not encounter issues too much. Dodge City was a case that you really had no choice getting into the long chain of traffic, unless your vehicle could handle going down wet, dirt roads, or if you bailed early to stay ahead of the hoards.
In my experience, chaser convergence is mixed. It doesn't happen during every chase and it doesn't always negatively impact the chase itself. Sometimes there aren't many issues at all, but there are times in which the convergence takes away from the pleasure and safety of storm chasing. When traffic slows from 70 MPH to 30 MPH with no opportunities to pass, then you're stuck. Maybe you shouldn't be that close in the first place, but part of chasing for many chasers is getting close. Most of us can handle getting close without problems, but as storms become more intense, there is less room for error. It's easy to see why a situation like El Reno could happen again. If you're in an area with no chasers, it's easy to bounce on an escape route. Hold up traffic due to convergence and then what might have been a 2-3 minute maneuver turns into 5 or 10 minutes. Add in wet roads, low visibility and strong winds, and the situation gets that much more dangerous.
My chase was essentially over by Vigo Park on 5/7/19, even though I arrived at the storm early and wasn't one of the many who were core-punching south as the storm approached the main road. I made a last ditch effort to bail south (which was away from the masses) and I was still held up by slow chaser traffic in the opposite direction.