I think there is a reason why biological systems have primarily evolved to use proteins for recognition, binding and catalysis. While it is true that DNA or RNA can do it, they don't generally have the same spectrum or affinity. So I think aptamers are likely to be useful in some applications, I would be surprised if they replaced antibodies overall. Recognize that people have been working with aptamers for nearly 20 years and the the successes are still somewhat limited.

I think there is a reason why biological systems have primarily evolved to use proteins for recognition, binding and catalysis. While it is true that DNA or RNA can do it, they don't generally have the same spectrum or affinity. So I think aptamers are likely to be useful in some applications, I would be surprised if they replaced antibodies overall. Recognize that people have been working with aptamers for nearly 20 years and the the successes are still somewhat limited.

I think that the whole Aptamer Versus Antibody paradigm is the wrong way to look at it. Antibodies are very good at what they do but they have hard limits in that they can only recognize peptide epitopes. Aptamers have been around for 25+ years, as Michael J. Benedik pointed out, but they were largely sidelined due to the overwhelming successes ushered in by the antibody revolution. Now that the limitations, and subsequent implications, of immunoglobulin-based epitope recognition have manifested, aptamers seem to be the best solution for targeting non-peptide biomolecules.

Many experiments were attempted in order to try and force antibody recognition of lipids, carbohydrates, and endogenous organic macromolecules, the best that any group could muster was mediocre affinity and specificity. I believe aptamers will be able expand the repertoire of potential targets, as we currently don't need to replace antibodies that function well, but we desperately need molecules that can selectively bind these other crucial molecules with high affinity.

I think for now they are an excellent supplement for the hard or impossible to target non-peptide biomolecules. The future, however, looks much brighter for aptamers than antibodies. The innovation and ingenuity of environment-sensitive aptamer switches that have been developed recently are awe-inspiring. The Hot Start Taq is nothing short of amazing: https://www.neb.com/tools-and-resources/feature-articles/using-aptamers-to-control-enzyme-activities-hot-start-taq-and-beyond . There are other groups searching for artificial riboswitches, pH-sensitive aptamers, even metal ion aptamer trafficking and switching, while the list of potential targets seems to be expanding exponentially with techniques like click-SELEX, which allows for the selection of aptamers that have been chemically modified to expand well beyond the canonical five nucleobases.

I think that the ability to chemically modify aptamers has a transformative capacity far beyond anything capable with antibodies, the DNA and RNA structures have essentially just become the framework upon which a near-infinite number of molecular-modulating chemicals can be organized in such a way as to facilitate selective interactions in an extremely effective manner. If human ingenuity brings engineering to the fray then we could be looking at the most powerful molecular manipulation tools imaginable, as the physics of these interactions are somewhat understandable (unlike proteins) with the help of modern computing. Although we may not understand the minutia of the convoluted interactions between macromolecules, we can emulate the evolutionary process at an exponentially accelerated rate by modulating the selection environments dynamically while selecting through enormous quantities of these divergent polymers. There is a reason why life started with RNA and DNA, these structures are able to direct and orchestrate chemistry with the highest possible level of control and efficiency. Even if we don't understand how or why, by emulating these systems we can extract further knowledge while simultaneously developing chemical tools that can convey levels of utility and potentiality beyond what our imaginations can currently conjure.