Even if you chase transfer deals it's possible to manage 10k domains by a one technically skilled person. Unfortunately most domainers I have seen on this forum and in other places are moderately computer illiterate. Most of them do domaining as a side business, are not full time domainers. So they do not have enough time to learn any computer skill.
This was one point when I said managing more than 200 domains is not an easy task.
Second point is;
You can't manage price updates, manual/direct sales and custom landing pages. You will eventually need to sell at marketplaces if you have more than 200 domains. Selling at marketplaces has advantages and disadvantages compared to direct sales.
More than 200 domains means a business model based on quantity. In my opinion it's more risky and offers low profit potential compared to less than 200 but higher priced, carefully picked domains.
Assume portfolio A has 10,000 and portfolio B has 200 domains.
Assume total worth of A = total worth B as a typical investor would have the same investment budget for domaining.
Problem starts here:
# domains in A / # domains in B = 50 = 10,000 /200
This means randomly chosen domain in B would have a 50 x price tag compared to a random domain in A.
Like, $500 vs $25,000 or $1,000 vs $50,000 or $ 3,000 vs $150,000 depending on total investment.
Questions:
1- Who will pay the renewal fees of extra 9,800 domain of the portfolio A ? 10,000 - 200 = 9,800.
2- Which is more likely? Selling a domain for $500 or $25,000 ?
If you say selling for $500 is more likely please think again about renewing extra 9,800 domains. 9,800 x $9 = $88k fees in renewal. Compare $500 in revenue vs $7,320 fee per month in renewals. You need to sell 50 x domains in portfolio A in the same time interval. In my opinion it's less likely. Because number of domain buyers is not too many regardless of the price.
You are artificially creating a problem and then trying to resolve it.
The only real time consuming part is acquiring. Managing is easy.
You don't have time, can't/don't want to hire a help?
1. Place all 10K names at 1 registrar.
2. Bulk upload into marketplace(s) with BIN prices.
3. Bulk upload to landing page provider service (or do it at the time of acquisition spending couple of minutes per name
4. Set auto-renew on names you are certain to keep
Enjoy it on autopilot, as most sales will come from BIN sales and spend 2-3 hrs/week responding to inquires, closing sales on offers etc.
As long as the quality of your names provide for sell through above around 0.4%, you'll be profitable. If you can reach 1% sell through, you will be making above $10K/month even after paying the renewals.
Again, I have just under 3000 names, I am spending maybe 1 hour/week renewing (not on auto on purpose), 1 hour responding to inquires etc.
Now, acquiring is different story. I spend almost 3-4 hours a day looking at the lists, bidding, listing at marketplaces etc.
I have algorithms in mind to save time on this phase too, but need to get to putting it into a task and ordering custom built scripts to handle this.
In short, managing thousands of names is easy, if you have organized it properly and are not chasing transfer deals. I'd rather focus on making 1 extra deal a year than run around trying to save $3000 on renewals.