Note that tape is still alive and well, in some A/V fields. Sony cameras use HDCAM tapes, which uses the highest compressed bitrate, besides uncompressed video. DV tapes, Betacam tapes, etc. are used by many independent videographers (less and less though, as many are switching to HDSLRs or high-end prosumer camcorders like the REDs) and news-gathering orgs (over-my-dead-body types).
In the music industry, tapes are used as masters for longevity.
The problem is a lack of accurate search capability (ie. how do I get to 00:32:30, and what content does that time have?) and slow transfer rate (typically 1:1, at least hopefully). In file-based formats, 00:32:30 would have a name, comments, and other metadata (all searchable), and it would be instantly accessible to the frame, and it can transfer as fast as the computer can encode.
To get the whole industry, top to bottom, to stick with tape would mean that:
1. Non-linear editors don't exist or remain in the five-figure cost range. That knocks out a major reason for switching from tape, as then linear editors would still be useful (and they were fucking horrible to use, trust me).
2. Computer development is horribly retarded, and storage space never develops to what it is today. For instance, hard drives never develop, and tape based storage remains. Nor does memory density develop. That would negate the usefulness of using a computer for media editing.
3. Tape is somehow speedy, and codecs are extremely efficient and don't have much data loss when compressing. ASB territory, in other words.