I used to work for a large multinational ($80b market cap; 55k+ employees) with a penchant for in-house development because vendor exhaustion is real and under-discussed in the business world.
Their trick for doing it was recruiting heavily in regions of the world with great junior dev talent at comparatively low costs (in their case Latin America, but it could be eastern Europe or elsewhere) and have them work with more senior middle and top managers to guide the architecture and technology decisions. At any given time, if you took a snapshot, you'd simultaneously have numerous SaaS subscriptions, numerous devs as described working to replace those same SaaS subscriptions, and numerous completed projects that, if purchased on the market, whether SaaS or not, would have cost exponentially more than the developers' salaries. No freelancing, no subcontracting, only proper employees - but yeah, you need to make the economics work and your milage will vary.
Full disclosure: I have since left that company and work as a consultant doing precisely that kind of work for others, it's only fair to note
Their trick for doing it was recruiting heavily in regions of the world with great junior dev talent at comparatively low costs (in their case Latin America, but it could be eastern Europe or elsewhere) and have them work with more senior middle and top managers to guide the architecture and technology decisions. At any given time, if you took a snapshot, you'd simultaneously have numerous SaaS subscriptions, numerous devs as described working to replace those same SaaS subscriptions, and numerous completed projects that, if purchased on the market, whether SaaS or not, would have cost exponentially more than the developers' salaries. No freelancing, no subcontracting, only proper employees - but yeah, you need to make the economics work and your milage will vary.
Full disclosure: I have since left that company and work as a consultant doing precisely that kind of work for others, it's only fair to note