“Unlimited” AI chat sounds simple. Pay once, talk forever.
In practice, it is one of the fastest ways an AI companion or chatbot business destroys its margins — and eventually its user trust.
This article explains why unlimited plans fail, how companies quietly claw them back, and why the emotional damage is often worse than the financial one. It also connects directly to the broader monetization failures explored in the pillar post:
→ Pillar:
👉 https://lizlis.ai/blog/how-ai-companion-apps-make-money-and-why-most-fail-2026/
The Non-Linear Cost Curve Nobody Markets
LLM inference costs scale with tokens, not users.
Each new message resends:
- The entire conversation history
- System prompts
- Memory summaries
- Sometimes images or tools
That means cost per message rises as conversations get longer.
A short, stateless Q&A costs cents per day.
A long-running companion chat with memory can cost 10–70× more.
In real AI app data:
- The top 10–20% of users consume 60–80% of total token spend
- One “power user” can cost as much as dozens of casual users
This makes “average cost per user” a lie.
LLM cost curves are long-tail and explosive.
Unlimited pricing assumes linearity.
Reality is brutally non-linear.
What “Unlimited” Actually Means in Practice
Almost no AI service that markets unlimited actually delivers it.
Instead, companies rely on quiet safeguards.
1. Fair-Use Caps (Hidden)
Some plans advertise “unlimited” but silently pause accounts once usage crosses a cost threshold.
A public example:
- Merlin AI — https://www.getmerlin.in/
Their “unlimited fair use” plan reportedly pauses accounts after roughly $100/month of usage, despite a ~$19 subscription.
Users usually find out only after getting locked out.
2. Soft Throttling
Instead of blocking access, services:
- Slow response times
- Add delays
- Lower priority for heavy users
Many ChatGPT Plus users (https://chat.openai.com/) have reported:
- Heavily used accounts becoming slower
- Fresh accounts responding faster on the same network
This is usage-based throttling — undocumented, but effective.
3. Silent Model Downgrades
Another cost-control trick:
- Early messages use premium models
- Later messages quietly switch to cheaper ones
Users don’t see an error.
They just feel the AI “got worse.”
OpenAI’s autoswitching behavior has been widely discussed after introducing automatic model routing in ChatGPT.
4. Memory and Context Resets
Unlimited chat almost never includes unlimited memory.
Common tactics:
- Truncating older messages
- Aggressive summarization
- Forcing new chats after context limits
This keeps token costs flat — at the expense of continuity.
For companion products, this directly undermines the emotional experience.
5. Behavioral Friction
Some AI companion apps subtly discourage long sessions:
- The AI suggests taking breaks
- Engagement drops after long usage
- Cooldowns appear without explanation
These are framed as “well-being features” — but they also protect margins.
Why This Feels Like Betrayal (Not Pricing)
In emotional AI products, “unlimited” is not a pricing term.
It is a relationship promise.
Users interpret unlimited as:
- Always available
- Always listening
- Never conditional
When limits appear, it doesn’t feel like SaaS friction.
It feels like rejection.
We have seen this before:
- When features are removed
- When memory disappears
- When access is throttled during emotional moments
User backlash is often intense, public, and permanent.
This is why pricing changes in AI companions cause far more churn than equivalent price increases.
Credits vs Subscriptions: The Core Dilemma
Credits (Economically Rational)
- Costs align with usage
- Heavy users pay more
- Margins stay intact
But users hate:
- Feeling metered
- Usage anxiety
- Surprise bills
Especially in emotional or creative use cases.
Subscriptions (Emotionally Comfortable)
- Predictable
- Encourages free expression
- Higher engagement
But:
- Heavy users can destroy margins
- Forces hidden limits later
- Trust breaks when reality surfaces
The “Unlimited Collapse” Timeline (Pattern)
This cycle repeats across AI apps:
- Launch: Generous unlimited access
- Growth: Heavy users emerge
- Cost Shock: Bills spike
- Clampdown: Limits, throttles, or price hikes
- Backlash: Users revolt
- Aftermath: Trust damaged, pricing rewritten
A widely discussed case:
- Cursor AI — https://www.cursor.sh/
Promised generous usage, then quietly replaced it with credit limits, triggering user outrage and public apologies.
Where Lizlis Fits Differently
Lizlis — https://lizlis.ai — intentionally avoids the “fake unlimited” trap.
Key differences:
- 50 daily message cap, clearly stated
- No hidden throttling
- No silent model downgrades
- Transparent limits users can plan around
Lizlis positions itself between an AI companion and an AI story platform:
- Emotional continuity matters
- But so does sustainability
- Expectations are set upfront
That transparency preserves trust — even when limits exist.
The Real Lesson
Unlimited AI chat is not impossible.
But pretending it is free is.
The apps that survive:
- Align pricing with real costs
- Avoid emotional bait-and-switch
- Set expectations early
- Choose transparency over illusion
Everything else eventually collapses.
Related pillar article:
👉 https://lizlis.ai/blog/how-ai-companion-apps-make-money-and-why-most-fail-2026/