If you want to play like David Bromberg, learn scales."
What if you have only 30 minutes a day, if lucky?
That's the whole point of been realistic. Setting the unacheavable goal is sure way to disaster.
I don't understand how it is possible to do even one single exersise in only 2 minutes. If you play one scale, on 2 beats, on 3 beats, stacatto and legato. Varying stacatto and legato, playing softly and increasing volume, then back to softly - it's 15 minutes easy, and you're not done yet.
Just running up and down the keyboard calling the notes aloud to memorize them is not really an exersise I'm talking about. Sure you need to do that once in a while, even every time will not take much effort.
But as far as "playing like David Bromberg" is concerned it is not that kind of "playing scales".
An exercise can be as short or as long as you want. What you describe is fairly comprehensive and time-consuming, and will practice multiple facets of your playing. Great if you have time for it, but if you don't there's no need to eschew it completely. Technique building exercises are not an all or nothing thing. The reason I practice the way I do is that it gradually builds my familiarity and ease with the instrument in a fairly general way. Just because it doesn't take 15 minutes doesn't mean that it isn't building technique - it just takes longer to see results.
You're absolutely right that you can't do every single technique exercise in 15 minutes or 1 hour or even 2 hours - you can always find more fundamentals to practice. But ask any teacher - any time at all you spend practicing those fundamentals is time well spent, and will pay dividends. Why not create a warm-up routine that varies from day to day(maybe one day - scales, another - broken thirds, another - staccato practice, etc., with a rotation that you stick to), but always lasts about three minutes? It takes discipline, sure (more discipline than I have, sadly), but if I did that, I'm sure my playing would be better than it is now, and it isn't a huge time investment. Technique exercises cam be tiresome, no doubt, and if you don't like them, don't do them. But there's no point in trying to rationalize that not doing them is making you a better player. That is simply false.