Hey Slava! I actually have a ton of experience with this. For the last year myself and my partners have built out Rocketlaunch (www.rocketlaunch.co) to a growth agency focused on marketing and sales for Startups.

We work on core items internally and outsource when possible.

My caveat on outsourcing would be to ensure the work is good. We have worked with outsourcers in the Phillipines and Colombia and had some great successes. We have also had issues where we have passed work across to a client where we didn't do enough QA and it was poor quality. If you can find partners that deliver good work, consistently, nurture them and reward them as much as possible. We have been working with an agency in Colombia to great success, but we've also cycled through a few that didn't work out.

QA is king, and if you can ensure the work is quality, reselling can be highly profitable (just ask any retailer).

Feel free to PM me if you want to have a more direct conversation!