Really, it has nothing to do with the Secret Service. The pivotal moment was when Vice President Pence’s security detail hustled him away from the mob to a safer location in the Capitol building on January 6th during the insurrection. The head of the VP’s security directed the VP to get into a waiting car. Mr. Pence said: “I am not getting into that car. I know you, but I don’t know them (apparently referring to the driver and other agents).”
So, the VP waited out the crisis and when the mob dispersed, he went back into chambers and completed his task, being the presiding officer over the electoral college vote count.
Imagine what would have happened if the VP had gotten into the car and it had whisked him away to a “safe house” (or worse, to a shallow grave near the Potomac). Lacking its presiding officer the meeting would have been effectively canceled, at least for the day. Or the Vice-chair could have stepped in to do Trump’s bidding.
So, why did the text messages disappear?
Those messages would have clearly indicated from whom the order to evacuate the VP came. If that person were the President or someone closely working with the President, well you can imagine the conclusions that might be drawn.
So, when did the text messages all “disappear”? It was before January 20th when the Biden Administration took over, so all of the actors were linked to the Trump administration. Knowing that the Secret Service agents would not lie under oath, they effected a “technology glitch” that resulted in all of the records of the texts sent on January 5/6 to be deleted. This would not prevent the Jan 6th Committee from subpoenaing the Secret Service Agents involved, but it would delay them, possibly beyond the tenure of any Congressional Committee or Department of Justice investigation (still hypothetical at that date).