Tech’s “product killer” claims keep missing the mark

Mainframes just posted their best revenue in 20 years. Email keeps growing fast. The bold replacement stories? They rarely match reality.

Back in 2013 Slack launched with big promises. Many headlines called it the tool that would kill email for good. Around the same time cloud platforms, containers, and orchestration tools got pitched as the end for mainframes. Jump to early 2026.

IBM’s mainframe business delivered its highest annual revenue in two decades, and people sent and billions of emails every day, with more growth ahead.

The “product killer” label still shows up everywhere in tech coverage. It grabs attention and turns complicated shifts into simple win-or-lose stories. But the numbers tell a different story. New tools usually sit alongside the old ones instead of wiping them out.

Mainframes keep delivering strong results

Predictions that mainframes would disappear started decades ago. Client-server setups in the 1990s. Cloud in the 2010s. Docker and Kubernetes were supposed to finish the job. None of that happened.

IBM reported full-year 2025 revenue of $67.5 billion, up 8 percent. Its infrastructure segment hit $15.72 billion. The IBM Z mainframe platform posted its strongest annual performance in 20 years, with Q4 revenue up 67 percent year-over-year (61 percent at constant currency).

CEO Arvind Krishna pointed to clear reasons. For certain workloads the mainframe still offers the lowest unit cost. It also delivers ironclad security and data control that large enterprises need. The new z17 system added a Spyre AI accelerator to make inline inferencing easier. IBM now expects total company revenue to grow more than 5 percent at constant currency in 2026.

Mainframes are not relics. They run high-value transactions and now handle AI tasks right where the data already lives.

Slack never replaced the inbox

Slack arrived with the same kind of hype. Early coverage in 2013 and 2014 labeled it the email killer outright. Founder Stewart Butterfield leaned into the idea at first, then later called email the cockroach of the internet, something that simply will not go away.

Email volume did not drop. It reached roughly 376 billion messages per day in 2025 and is projected to climb toward 392 billion in 2026, growing at about 4 percent annually. The number of email users worldwide sits near 4.6 billion and heads toward 4.7 billion by the end of 2026.

Slack became a solid product inside Salesforce, but its growth slowed as the company matured. Salesforce overall revenue growth settled into the 8 to 9 percent range in recent quarters after years of 20-plus percent jumps. Slack still cuts internal email for many teams by about a third, yet it never took over external communication, legal records, or customer outreach.

The tools serve different jobs. Slack handles fast team chats. Email manages async, auditable, and external messages. They work together.

Why the killer label sticks around anyway

This phrasing feels good. It turns platform economics into a contest. It makes the new arrival sound revolutionary and gives writers a clear angle that spreads quickly. In a crowded feed, simple drama wins eyes and clicks.

Practitioners see the pattern every day. Workloads shift when the real economics, security needs, or performance gains line up and become worth chasing. Not because someone coined a catchy phrase.

Mainframes last because of transaction integrity and compliance rules. Email lasts because every partner, regulator, and customer already uses it.

The actual change is almost always specialization and layering. Cloud did not kill on-prem data centers. It pushed them to improve. Containers did not kill virtual machines. They made them more efficient. Slack did not kill email. It gave teams a quicker channel for the messages that never needed formal inboxes.

What to track instead of the hype

Skip the killer headlines. Focus on three practical things:

• Unit economics for your exact workloads
• Data sovereignty and compliance demands
• How easily the new tool connects to everything already running the business

When those line up, adoption happens naturally, often without killing anything.

The product-killer era delivered some fun stories. In 2026 it feels as tired as every online story being labeled “Breaking News”.

The technologies worth real attention are the ones that quietly make the old ones better, not the ones promising to bury them.