If virtual comp is as you described where teams actually go to a venue and perform then yes , a lot of the overhead/costs to put on the comp remain the same. The virtual aspect is really in relation to spectators.
However the Varsity virtual competition series is charging $39 per athlete, each performance. And crossovers pay that $39 for each team. That is for competitions where you literally perform in your own gym and send them a video submission. In that case then it is only judges time that is the overhead. And that is a ridiculous cost. Say a team has 20 kids. That is a cost of $780 for judges to score 2 1/2 minutes of a routine. 3 judges on a panel? How much do judges make? Are they paid hourly or per routine scored? How much is Varsity making per team when they do not even have to pay for the vast majority of the cost of running a comp.
Because this is what I would anticipate happening. If people are willing to pay $39 pp to perform in their own gym, then they will raise prices of comp participation astronomically when they are allowed to return to venues and they will blame it on the cost of the venue.
Where do you think spectator fees go that Varsity is not collecting when comps are virtual? NCA All Star Nationals attracted 38,000 spectators over the course of the weekend,
per their website. I can't find how much spectator fees cost. If it was $50 for the weekend (cost of 2 tickets for the 2 days of competition), 38,000 x 5$0 is almost $2 million. Surely enough to help cover the cost of the venue, contracted venue staff, parking, local government participation, insurance, and all other related fees to accomodate 50,000 people in two days.
A competition is a product the Varsity offers. There is nowhere in all of business where the cost of the product relies solely on what you get. A hamburger from McDonalds is not the cost of the bun, patty, and toppings. It is all of that plus workers salaries and property tax and water bills and equipment maintenance and electricity and insurance for the store. And its the cost of marketing/advertising, research and innovation, transport of supplies, etc at the corporate level.
So it is not "$39 to perform in your own gym". You can go perform in your own gym for free, no one is stopping you. It is $39 to participate in Varsity's product that pays for all of Varsity's costs. Same arguement could be said for participating in marathons and a variety of other events.
ETA: I don't see how Varsity's expenses have drastically been cut due to COVID. The costs of employee salaries, property taxes, bulding rent, utilities, equipment maintence, event planning, communication, insurance, marketing, etc still exist whether competitions are virtual or not. The business is still running.