what if the expensive SAAS offering is just as vibe coded and poor quality as what a junior offers?
At the end of the day these decisions are all series of trade-offs, and the trick is understanding your requirements and capabilities well enough to make the right trade-offs.
The second question is a valid one, and I think it will somewhat raise the bar of what successful SAAS vendors will have to offer in coming years
Somehow that has not happened yet in 2026.
A typical SaaS customer will use many pieces of software (we mostly call them SaaS now) across its various functions: HR, accounting, CRM, etc. Each one of those will have access to the same pool of senior devs and AI tools, but they will pour more resources into each area and theoretically deliver better software.
The bigger issue here is the economics of the C-suite have not changed here. Assume a 100 CPG company uses 10-20 SaaS apps. Salesforce might be $100k/year or whatever. 1Password is $10k. Asana $10k. etc. They add up, but on the other hand it is not productive to task a $150k employee with rebuilding a $10k tool. And even with AI, it would take a lot of effort to make something that will satisfy a team accustomed to any modern SaaS tool like Salesforce or Atlassian. (Engineers will not even move off Github, and it's literally built on free software.)
That's before I get to sensitive areas. Do you want to use a vibe-coded accounting system? Inventory system? Payroll? You can lose money, employees, and customer perception very rapidly due to some bugs. Who wants to be responsible for all their employee passwords are compromised because they wanted to save $800/mo?
Then, the gains from cutting SaaS are capped. You can only cut your SaaS spend to zero. On the other hand, if you have those engineers you can point them at niche problems in your business niche (which you know better than anyone) and create conditions for your business to grow faster. The returns from this are uncapped.
TL;DR; it's generally not a great idea to build in-house unless your requirements are essentially bespoke.
If your senior developers can slap together something better than an expensive SAAS offering you want them directing that energy at your core products/services rather than supporting tools.
And the people deciding to buy the expensive SAAS tools are often not the people using them, and typically don't care too much about how crappy the tool may or may not be for doing the job it's advertising as doing.
The gains is generally more seen outside of monetary as these SaaS solutions where holding us back for achieving our goals and improving our services to our customers. As in the end of the day our customers do not care if "insert SaaS" is having issues, it will always be our problem to own.