Conventional wisdom would suggest the opposite: the big companies with more resources will obviously just decide to create their own internal version, whereas the small companies don’t have the time or resources to do that.
What actually seems to happen is that IMO if a team is nimble enough to copy a SaaS product internally, and doesn’t want to pay the $100-$1000 a month for your services, they’ll likely build it in house with AI.
However if the company is large enough, it’s coalesced into different departments with specific resources and plans, and ergo no one wants to give themselves a ton of new work when they can just outsource it to a SaaS and get corporate to pay for it.